Search results for: waste flow

Authors: Young Min Kim, Dong Gil Shin, Assmelash Assefa Negash

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This study describes the application of a single loop organic Rankine cycle (ORC) for recovering waste heat from an excavator. In the case of waste heat recovery of the excavator, the heat of hydraulic oil can be used in the ORC system together with the other waste heat sources including the exhaust gas and engine coolant. The performances of four different cases of single loop ORC systems were studied at the main operating condition, and critical design factors are studied to get the maximum power output from the given waste heat sources. The energy and exergy analysis of the cycles are performed concerning the available heat source to determine the best fluid and system configuration. The analysis demonstrates that the ORC in the excavator increases 14% of the net power output at the main operating condition with a simpler system configuration at a lower expander inlet temperature than in a conventional vehicle engine without the heat of the hydraulic oil.

Keywords: engine, excavator, hydraulic oil, organic Rankine cycle (ORC), waste heat recovery

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Authors: Supriya Mahida, Sangita, Yogesh U. Shah, Shanta Kumar

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The global production of thermocol increasing day by day, due to vast applications of the use of thermocole in many sectors. Thermocol being non-biodegradable and more toxic than plastic leads towards a number of problems like its management into value-added products, environmental damage and landfill problems due to weight to volume ratio. Utilization of waste thermocol for modification of bitumen binders resulted in waste thermocol modified bitumen (WTMB) used in road construction and maintenance technology. Modification of bituminous mixes through incorporating thermocol into bituminous mixes through a dry process is one of the new options besides recycling process which consumes lots of waste thermocol. This process leads towards waste management and remedies against thermocol waste disposal. The present challenge is to dispose the thermocol waste under different forms in road infrastructure, either through the dry process or wet process to be developed in future. This paper focuses on the use of thermocol wastes which is mixed with VG 10 bitumen in proportions of 0.5%, 1%, 1.5%, and 2% by weight of bitumen. The physical properties of neat bitumen are evaluated and compared with modified VG 10 bitumen having thermocol. Empirical characterization like penetration, softening, and viscosity of bitumen has been carried out. Thermocol and waste thermocol modified bitumen (WTMB) were further analyzed by Fourier Transform Infrared Spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), and Dynamic Shear Rheometer (DSR).

Keywords: DSR, FESEM, FT-IR, thermocol wastes

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Authors: Tolulope A. Olukunle

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Plastic waste management has emerged as one of the greatest challenges facing developing countries. This paper describes the design of various components of a plastic shredder. This machine is widely used in industries and recycling plants. The introduction of plastic shredder machine will promote reduction of post-consumer plastic waste accumulation and serves as a system for wealth creation and empowerment through conversion of waste into economically viable products. In this design research, a 10 kW electric motor with a rotational speed of 500 rpm was chosen to drive the shredder. A pulley size of 400 mm is mounted on the electric motor at a distance of 1000 mm away from the shredder pulley. The shredder rotational speed is 300 rpm.

Keywords: design, machine, plastic waste, recycling

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Authors: Girts Zageris, Vadims Geza, Andris Jakovics

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Gasification processes are of great interest due to their generation of renewable energy in the form of syngas from biodegradable waste. It is, therefore, important to study the factors that play a role in the efficiency of gasification and the longevity of the machines in which gasification takes place. This study focuses on the latter, aiming to optimize an entrained-flow gasifier by reducing slag formation on its walls to reduce maintenance costs. A CFD mathematical model for an entrained-flow gasifier is constructed – the model of an actual gasifier is rendered in 3D and appropriately meshed. Then, the turbulent gas flow in the gasifier is modeled with the realizable k-ε approach, taking devolatilization, combustion and coal gasification into account. Various such simulations are conducted, obtaining results for different air inlet positions and by tracking particles of varying sizes undergoing devolatilization and gasification. The model identifies potential problematic zones where most particles collide with the gasifier walls, indicating risk regions where ash deposits could most likely form. In conclusion, the effects on the formation of an ash layer of air inlet positioning and particle size allowed in the main gasifier tank are discussed, and possible solutions for decreasing a number of undesirable deposits are proposed. Additionally, an estimate of the impact of different factors such as temperature, gas properties and gas content, and different forces acting on the particles undergoing gasification is given.

Keywords: biomass particles, gasification, slag formation, turbulence k-ε modelling

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Authors: Anike Akinrinlade

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The world population is estimated to grow from 7.1 billion to 9.22 billion by 2075, increasing therefore by 23% from the current global population. Much of the demographic changes up to 2075 will take place in the less developed regions. There are currently 54 countries which fall under the bracket of being defined as having ‘low-middle income’ economies and need new ways to generate valuable products from current resources that is available. Artemisia annua L is well used for the extraction of the phytochemical artemisinin, which accounts for around 0.01 to 1.4 % dry weight of the plant. Artemisinin is used in the treatment of malaria, a disease rampart in sub-Saharan Africa and in many other countries. Once artemisinin has been extracted the spent leaf and waste streams are disposed of as waste. A feasibility study was carried out looking at increasing the biomass value of A. annua, by designing a biorefinery where spent leaf and waste streams are utilized for high product generation. Quercetin, ferulic acid, dihydroartemisinic acid, artemisinic acid and artemsinin were screened for in the waste stream samples and the spent leaf. The analytical results showed that artemisinin, artemisinic acid and dihydroartemisinic acid were present in the waste extracts as well as camphor and arteannuin b. Ongoing effects are looking at using more industrially relevant solvents to extract the phytochemicals from the waste fractions and investigate how microwave pyrolysis of spent leaf can be utilized to generate bio-products.

Keywords: high value product generation, bioinformatics, biomedicine, waste streams, spent leaf

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Authors: F. A. Hamad, S. He

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In this paper, the average heat transfer characteristics for a cross flow cylinder of 16 mm diameter in a vertical pipe has been studied for single-phase flow (water/oil) and multicomponent (non-boiling) flow (water-air, water-oil, oil-air and water-oil-air). The cylinder is uniformly heated by electrical heater placed at the centre of the element. The results show that the values of average heat transfer coefficients for water are around four times the values for oil flow. Introducing air as a second phase with water has very little effect on heat transfer rate, while the heat transfer increased by 70% in case of oil. For water–oil flow, the heat transfer coefficient values are reflecting the percentage of water up to 50%, but increasing the water more than 50% leads to a sharp increase in the heat transfer coefficients to become close to the values of pure water. The enhancement of heat transfer by mixing two phases may be attributed to the changes in flow structure near to cylinder surface which lead to thinner boundary layer and higher turbulence. For three-phase flow, the heat transfer coefficients for all cases fall within the limit of single-phase flow of water and oil and are very close to pure water values. The net effect of the turbulence augmentation due to the introduction of air and the attenuation due to the introduction of oil leads to a thinner boundary layer of oil over the cylinder surface covered by a mixture of water and air bubbles.

Keywords: circular cylinder, cross flow, hear transfer, multicomponent multiphase flow

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Authors: S. P. Sharma, Som Nath Saha

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This paper deals with the analytical investigation of thermal and thermohydraulic performance of double flow solar air heaters with corrugated and flat plate absorber. A mathematical model of double flow solar air heater has been presented, and a computer program in C⁺⁺ language is developed to estimate the outlet temperature of air for the evaluation of thermal and thermohydraulic efficiency by solving the governing equations numerically using relevant correlations for heat transfer coefficients. The results obtained from the mathematical model is compared with the available experimental results and it is found to be reasonably good. The results show that the double flow solar air heaters have higher efficiency than conventional solar air heater, although the double flow corrugated absorber is superior to that of flat plate double flow solar air heater. It is also observed that the thermal efficiency increases with increase in mass flow rate; however, thermohydraulic efficiency increases with increase in mass flow rate up to a certain limit, attains the maximum value, then thereafter decreases sharply.

Keywords: corrugated absorber, double flow, solar air heater, thermos-hydraulic efficiency

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Authors: Mehrdad Abkenari, Alireza Rezaei, Naghmeh Pournayeb

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There have recently been many studies and investments in developed and developing countries regarding the possibility of recycling construction waste, which are still ongoing. Since the term 'construction waste' covers a vast spectrum of materials in constructing buildings, roads and etc., many investigations are required to measure their technical performance in use as well as their time and place of use. Concrete is among the major and fundamental materials used in current construction industry. Along with the rise of population in developing countries, it is desperately required to meet the people's primary need in construction industry and on the other hand, dispose existing wastes for reducing the amount of environmental pollutants. Restrictions of natural resources and environmental pollution are the most important problems encountered by civil engineers. Reusing construction waste is an important and economic approach that not only assists the preservation of environment but also, provides us with primary raw materials. In line with consistent municipal development in disposal and reuse of construction waste, several approaches including, management of construction waste and materials, materials recycling and innovation and new inventions in materials have been predicted. This article has accordingly attempted to study the activities related to recycling of construction wastes and then, stated the economic, quantitative, qualitative and environmental results obtained.

Keywords: civil engineering, environment, recycling, construction waste

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Authors: Arun Goel, D. V. S. Verma, Sanjeev Sangwan

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The present study was aimed to develop a discharge measuring device for irrigation and laboratory channels. Experiments were conducted on a sharp edged constricted flow meters having four types of width constrictions namely 2:1, 1.5:1, 1:1, and 90o in the direction of flow. These devices were made of MS sheets and installed separately in a rectangular flume. All these four devices were tested under free and submerged flow conditions. Eight different discharges varying from 2 lit/sec to 30 lit/sec were passed through each device. In total around 500 observations of upstream and downstream depths were taken in the present work. For each discharge, free submerged and critical submergence under different flow conditions were noted and plotted. Once the upstream and downstream depths of flow over any of the device are known, the discharge can be easily calculated with the help of the curves developed for free and submerged flow conditions. The device having contraction 2:1 is the most efficient one as it allows maximum critical submergence.

Keywords: flowrate, flowmeter, open channels, submergence

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Authors: H. Bayat, M. Majidi, M. Bolhasani, A. Karbalaie Alilou, A. Mirabdolah Lavasani

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Unsteady flow and heat transfer from a circular cylinder in cross-flow is studied numerically. The governing equations are solved by using finite volume method. Reynolds number varies in range of 50 to 200, in this range flow is considered to be laminar and unsteady. Al2O3 nanoparticle with volume fraction in range of 5% to 20% is added to pure water. Effects of adding nanoparticle to pure water on lift and drag coefficient and Nusselt number is presented. Addition of Al2O3 has inconsiderable effect on the value of drags and lift coefficient. However, it has significant effect on heat transfer; results show that heat transfer of Al2O3 nanofluid is about 9% to 36% higher than pure water.

Keywords: nanofluid, heat transfer, unsteady flow, forced convection, cross-flow

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Authors: Ainul Haque, Ameeye Kumar Nayak

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Flow enhancement and species transport in a slit hydrophobic microchannel is studied for non-Newtonian fluids with the externally imposed electric field and pressure gradient. The incompressible Poisson-Nernst-Plank equations and the Navier-Stokes equations are approximated by lubrication theory to quantify the flow structure due to hydrophobic and hydrophilic surfaces. The analytical quantification of velocity and pressure of electroosmotic flow (EOF) is made with the numerical results due to the staggered grid based finite volume method for flow governing equations. The resistance force due to fluid friction and shear force along the surface are decreased by the hydrophobicity, enables the faster movement of fluid particles. The resulting flow enhancement factor Ef is increased with the low viscous fluid and provides maximum species transport. Also, the analytical comparison of EOF with pressure driven EOF justifies the flow enhancement due to hydrophobicity and shear impact on flow variation.

Keywords: electroosmotic flow, hydrophobic surface, power-law fluid, shear effect

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Authors: Hiroshi Katanoda, Mohd Hazwan bin Yusof

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A theoretical investigation from the viewpoint of gas-dynamics and thermodynamics was carried out, in order to clarify the energy separation mechanism in a viscous compressible vortex, as a primary flow element in a uni-flow vortex tube. The mathematical solutions of tangential velocity, density and temperature in a viscous compressible vortical flow were used in this study. It is clear that a total temperature in the vortex core falls well below that distant from the vortex core in the radial direction, causing a region with higher total temperature, compared to the distant region, peripheral to the vortex core.

Keywords: energy separation mechanism, theoretical analysis, vortex tube, vortical flow

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Authors: Alireza Mehdizadeh, Ghanbarali Sheikhzadeh

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In this paper the pressure loss of drilling fluid flow in the annulus is investigated. On this purpose the domains between two concentric and two eccentric cylinders are considered as computational domains. In this research foam is used as drilling fluid. Firstly simulation results for laminar flow and non Newtonian fluid and different density like 100, 200, 300 kg/m3 and different inner cylinder rotational velocity like 100, 200, 300 RPM is presented. These results are compared and matched with references results. The power law and Herschel Bulkly methods are used for non Newtonian fluid modeling. After that computations are repeated with turbulence flow considering. K- Model is used for turbulence modeling. Results show that in laminar flow Herschel bulkly model has best result in comparison with power law model. And pressure loss in turbulence flow is higher than laminar flow.

Keywords: simulation, concentric cylinders, drilling, non Newtonian

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Authors: Pradip Baishya, D. K. Mahanta

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Rapid and unplanned urbanisation in most cities of India has progressively increased the problem of managing municipal waste in the past few years. With insufficient infrastructure and funds, Municipalities in most cities are struggling to cope with the pace of waste generated. Open dumping is widely in practice as a cheaper option. Scientific disposal of waste in such a large scale with the elements of segregation, recycling, landfill, and incineration involves sophisticated and expensive plants. In an effort to finding affordable and simple solutions to address this burning issue of waste disposal, a semi-mechanized plant has been designed underlying the concept of a zero waste community. The fabrication work of the waste management unit is carried out by local skills from locally available materials. A resident colony in the city of Guwahati has been chosen, which is seen as a typical representative of most cities in India in terms of size and key issues surrounding waste management. Scientific management and disposal of waste on site is carried out on the principle of reduce, reuse and recycle from segregation to compositing. It is a local community participatory model, which involves all stakeholders in the process namely rag pickers, residents, municipality and local industry. Studies were conducted to testify the plant as revenue earning self-sustaining model in the long term. Current working efficiency of plant for segregation was found to be 1kg per minute. Identifying bottlenecks in the success of the model, data on efficiency of the plant, economics of its fabrication were part of the study. Similar satellite waste management plants could potentially be a solution to supplement the waste management system of municipalities of similar sized cities in India or South East Asia with similar issues surrounding waste disposal.

Keywords: affordable, rag pickers, recycle, reduce, reuse, segregation, zero waste

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Authors: Ching-Hsu Huang, Si-Qing Hong

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The main purpose of this study is to understand the consumers’ perceptions and attitudes toward food waste in restaurants. The questionnaires were conducted as a research tool to collect data to understand consumers’ food waste behaviors and the most food wasted in terms of their preparation in the restaurant. The subjects were the consumers in the restaurants and asked to fill out the questionnaire, including social responsibility, attitude, behavioral intention and food waste behaviors. 89 questionnaires were collected and the data were analyzed by reliability, descriptive analysis, t-test and ANOVA. The five hypotheses were examined and the results showed there is a significant relationship between social responsibility and behavioral intention; social responsibility and attitude, attitude and behavioral intention. The suggestions and implications were addressed for restauranteurs and further research.

Keywords: food waste behaviors (FWB), social responsibility, consumer attitude, behavioral intention, restaurants

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Authors: Qiuhao Chang, Liangliang Huang, Xingru Wu

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In the United States, over 90% of the roads are paved with asphalt. The aging of asphalt is the most serious problem that causes the deterioration of asphalt pavement. Waste cooking oils (WCOs) have been found they can restore the properties of aged asphalt and promote the reuse of aged asphalt pavement. In our previous study, it was found the optimal WCO concentration to restore the aged asphalt sample should be in the range of 10~15 wt% of the aged asphalt sample. After the WCO concentration exceeds 15 wt%, as the WCO concentration increases, some important properties of the asphalt sample can be weakened by the addition of WCO, such as cohesion energy density, surface free energy density, bulk modulus, shear modulus, etc. However, maximizing the utilization of WCO can create environmental and economic benefits. Therefore, in this study, a new idea about using the waste polymer is another additive to restore the WCO modified asphalt that contains a high concentration of WCO (15-25 wt%) is proposed, which has never been reported before. In this way, both waste polymer and WCO can be utilized. The molecular dynamics simulation is used to study the effect of waste polymer on properties of WCO modified asphalt and understand the corresponding mechanism at the molecular level. The radial distribution function, self-diffusion, cohesion energy density, surface free energy density, bulk modulus, shear modulus, adhesion energy between asphalt and aggregate are analyzed to validate the feasibility of combining the waste polymer and WCO to restore the aged asphalt. Finally, the optimal concentration of waste polymer and WCO are determined.

Keywords: reclaim aged asphalt pavement, waste cooking oil, waste polymer, molecular dynamics simulation

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Authors: Hyun-Kyu Cho, Jun-Su Kim, Choon-Geun Huh, Geon Lee Young-Chul Park

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In this study, the relationship between flow properties and fluid projection distance look into connection for shape variations of foam monitor. A numerical analysis technique for fluid analysis of a foam monitor was developed for the prediction. Shape of foam monitor the flow path of fluid flow according to the shape, The fluid losses were calculated from flow analysis result.. The modified model used the length increase model of the flow path, and straight line of the model. Inlet pressure was 7 [bar] and external was atmosphere codition. am. The results showed that the length increase model of the flow path and straight line of the model was improved in the nozzle projection distance.

Keywords: injection performance, finite element method, foam monitor, Projection distance

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Authors: Mohand Kessal, Rachid Boucetta, Mourad Tikobaini, Mohammed Zamoum

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Leakage problem of two-component fluids flow is modeled for a transient one-dimensional homogeneous bubbly flow and developed by taking into account the effect of a leak located at the middle point of the pipeline. The corresponding three conservation equations are numerically resolved by an improved characteristic method. The obtained results are explained and commented in terms of physical impact on the flow parameters.

Keywords: fluid transients, pipelines leaks, method of characteristics, leakage problem

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Authors: Kunwar Mrityunjai Sharma, Trilok Nath Singh

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The Navier-Stokes equation is used to study nonlinear fluid flow in rough 2D fractures. The major goal is to investigate the influence of inertial flow owing to fracture wall roughness on nonlinear flow behavior. Roughness profiles are developed using Barton's Joint Roughness Coefficient (JRC) and used as fracture walls to assess wall roughness. Four JRC profiles (5, 11, 15, and 19) are employed in the study, where a higher number indicates higher roughness. A parametric study has been performed using varying pressure gradients, and the corresponding Forchheimer number is calculated to observe the nonlinear behavior. The results indicate that the fracture roughness has a significant effect on the onset of nonlinearity. Additionally, the validity of the cubic law is evaluated and observed that it overestimates the flow in rough fractures and should be used with utmost care.

Keywords: fracture flow, nonlinear flow, cubic law, Navier-stokes equation

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Authors: Wajeeha A. Qazi, Mohammed-Hasham Azam, Umais A. Mehmood, Ghithaa A. Al-Mufragi, Noor-Alhuda Alrawahi, Mohammed F. M. Abushammala

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Municipal Solid Waste (MSW) disposed in landfill sites decompose under anaerobic conditions and produce gases which mainly contain carbon dioxide (CO₂) and methane (CH₄). Methane has the potential of causing global warming 25 times more than CO₂, and can potentially affect human life and environment. Thus, this research aims to determine MSW generation and the annual CH₄ emissions from the generated waste in Oman over the years 1971-2030. The estimation of total waste generation was performed using existing models, while the CH₄ emissions estimation was performed using the intergovernmental panel on climate change (IPCC) default method. It is found that total MSW generation in Oman might be reached 3,089 Gg in the year 2030, which approximately produced 85 Gg of CH₄ emissions in the year 2030.

Keywords: methane, emissions, landfills, solid waste

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Authors: İ. Çelik, Goksel Demirer

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Turkey is the third largest producer of pistachio (Pistacia vera L.) after Iran and United States. Harvested pistachio nuts are covered with organic hull which is removed by de-hulling process. Most of the pistachio by-products which are produced during de-hulling process are considered as agricultural waste and often mixed with soil, to a lesser extent are used as feedstuff by local livestock farmers and a small portion is used as herbal medicine. Due to its high organic and phenolic content as well as high solids concentration, pistachio processing wastes create significant waste management problems unless they are properly managed. However, there is not a well-established waste management method compensating the waste generated during the processing of pistachios. This study investigated the anaerobic treatability and biogas generation potential of pistachio hull waste. The effect of pre-treatment on biogas generation potential was investigated. For this purpose, Biochemical Methane Potential (BMP) Assays were conducted for two Chemical Oxygen Demand (COD) concentrations of 22 and 33 g tCOD l-1 at the absence and presence of chemical and thermal pre-treatment methods. The results revealed anaerobic digestion of the pistachio de-hulling wastes and subsequent biogas production as a renewable energy source are possible. The observed percent COD removal and methane yield values of the pre-treated pistachio de-hulling waste samples were significantly higher than the raw pistachio de-hulling waste. The highest methane yield was observed as 213.4 ml CH4/g COD.

Keywords: pistachio de-hulling waste, biogas, renewable energy, pre-treatment

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Authors: Joseph Govha, Sharon Mudutu

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The research details the treatment of distillery waste water by making use of activated carbon prepared from orange peels as an adsorbent. Adsorption was carried out at different conditions to determine the optimum conditions that work best for the removal of color in distillery waste water using orange peel activated carbon. Adsorption was carried out at different conditions by varying contact time, adsorbent dosage, pH, testing for color intensity and Biological Oxygen Demand. A maximum percentage color removal of 88% was obtained at pH 7 at an adsorbent dosage of 1g/20ml. Maximum adsorption capacity was obtained from the Langmuir isotherm at R2=0.98.

Keywords: distillery, waste water, orange peel, activated carbon, adsorption

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Authors: M. A. Ojo, E. O. Ogbole, A. O. Ojo

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This study analysed improved household solid waste management system in Minna metropolis, Niger state. Multi-staged sampling technique was used to administer 155 questionnaires to respondents, where Minna was divided into two income groups A and B based on the quality of the respondent’s houses. Primary data was collected with the aid of structured questionnaires and analysed using descriptive statistics to obtain results for the socioeconomic characteristics of respondents, types of waste generated and methods of disposing solid waste, the level of awareness and reliability of waste disposal methods as well as the willingness of households to pay for solid waste management in the area. The results revealed that majority of the household heads in the study area were male, 94.20% of the household heads fell between the ages of 21 and 50 and also that 96.80% of them had one form of formal education or the other. The results also revealed that 47.10% and 43.20% of the households generated food wastes and polymers respectively as a major constituent of waste disposed. The results of this study went further to reveal that 81.90% of the household heads were aware of the use of collection cans as a method of waste disposal while only 32.90% of them considered the method highly reliable. Multiple regression was used to determine the factors affecting the willingness of households to pay for waste disposal in the study area. The results showed that 76.10% of the respondents were willing to pay for solid waste management which indicates that households in Minna are concerned and willing to cater for their immediate environment. The multiple regression results revealed that age, income, environmental awareness and household expenditure have a positive and statistically significant relationship with the willingness of households to pay for waste disposal in the area while household size has a negative and statistically significant relationship with households’ willingness to pay. Based on these findings, it was recommended that more waste management services be made readily available to residents of Minna, waste collection service should be privatised to increase their effectiveness through increased competition and also that community participatory approach be used to create more environmental awareness amongst residents.

Keywords: household, solid waste, management, WTP

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Authors: Aimad Koulali

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Flow structure evolution around a single pair of Delta vortex generators (VGs) is studied numerically. For laminar, transient, and turbulent flow regimes, numerical simulations have been performed in a duct with a pair of Delta vortex generators. The finiteelementmethodwasused to simulate the flow. To formulate the fluid structure interaction problem, the ALE formulation was used. The aim of this study is to provide a detailed insight into the generation and dissipation of longitudinal vortices over a wide range of flow regimes, including the laminar-turbulent transition. A wide range of parameters has been exploited to describe the inducedphenomenawithin the flow. Weexaminedvariousparametersdepending on the VG geometry, the flow regime, and the channel geometry. A detailed analysis of the turbulence and wall shear stress properties has been evaluated. The results affirm that there are still optimal values to obtain better performing vortices in order to improve the exchange performance.

Keywords: finte element method, deformable vortex generator, numerical analysis, fluid structure interaction, ALE formlation, turbulent flow

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Authors: B. Yanıktepe, C. Özalp, B. Şahin

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Delta wing planform is an essential aerodynamic configuration, which could be effectively used at relatively high angles of attack than conventional wings in subsonic flow conditions. The flow over delta wings can be characterized by a pair of leading edge vortices emanating from wing apex. Boundary layer separation causes these vortical structures formed by rolling up of viscous flow sheet. This flow separation mechanism is occurred due to angle of attack and sharp leading edges of the delta wing. Therefore, complexity and variety in planform designs rise to catch the best under abnormal flow conditions. The present experimental study investigates the near surface flow structure and aerodynamic flow characteristics of X-45 type non-slender delta wing planform using dye visualization, Stereoscopic Particle Image Velocimetry (stereo-PIV). The instantaneous images are acquired on the plan-view plane within 5o≤α≤20o to calculate the time-averaged flow data. It can be concluded that vortical flow with a pair of well-defined LEVs over X-45 develop at very low angles of attack, secondary vortex are also evident and form close to the wing surface similar to delta and lambda planforms. The stall occurs at an angle of attack α=32o.

Keywords: aerodynamic, delta wing, PIV, vortex breakdown

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Authors: Usman Jilani, Ibad Khurram, Irshad Hussain

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Environmentally sustainable waste management is a challenging task as it involves multiple and diverse economic, environmental, technical and regulatory issues. Municipal Solid Waste Management (MSWM) is more challenging in developing countries like Pakistan due to lack of awareness, technology and human resources, insufficient funding, inefficient collection and transport mechanism resulting in the lack of a comprehensive waste management system. This work presents an overview of current MSWM practices in Peshawar, the provincial capital of Khyber Pakhtunkhwa, Pakistan and proposes a better and sustainable integrated solid waste management system with incineration (Waste to Energy) option. The diverted waste would otherwise generate revenue; minimize land fill requirement and negative impact on the environment. The proposed optimized solution utilizing scientific techniques (like mathematical modeling, optimization algorithms and GIS) as decision support tools enhances the technical & institutional efficiency leading towards a more sustainable waste management system through incorporating: - Improved collection mechanisms through optimized transportation / routing and, - Resource recovery through incineration and selection of most feasible sites for transfer stations, landfills and incineration plant. These proposed methods shift the linear waste management system towards a cyclic system and can also be used as a decision support tool by the WSSP (Water and Sanitation Services Peshawar), agency responsible for the MSWM in Peshawar.

Keywords: municipal solid waste management, incineration, mathematical modeling, optimization, GIS, Peshawar

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Authors: Imane Benghalia, Mohammed Zamoum, Rachid Boucetta

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Hydrodynamic cavitation is a complex physical phenomenon that appears in hydraulic systems (pumps, turbines, valves, Venturi tubes, etc.) when the fluid pressure decreases below the saturated vapor pressure. The works carried out in this study aimed to get a better understanding of the cavitating flow phenomena. For this, we have numerically studied a cavitating bubbly flow through a Venturi nozzle. The cavitation model is selected and solved using a commercial computational fluid dynamics (CFD) code. The obtained results show the effect of the inlet pressure (10, 7, 5, and 2 bars) of the Venturi on pressure, the velocity of the fluid flow, and the vapor fraction. We found that the inlet pressure of the Venturi strongly affects the evolution of the pressure, velocity, and vapor fraction formation in the cavitating flow.

Keywords: cavitating flow, CFD, phase change, venturi

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Authors: Alireza Rafie Boldaji, Ahmad Saboonchi

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Chokes are commonly used in oil and gas production systems. A choke is a restriction basically designed to control flow rates of oil and gas wells, to prevent the downstream disturbances from propagating upstream (critical flow), and to protect the surface equipment facilities against slugging at high flowing pressures. There are different methods to calculate the multiphase flow rate, one of the multiphase flow measurement methods is the separation and measurement by on¬e-phaseFlow meter, another common method is the use of movable separator, their operations are very labor-intensive and costly. The current method used is based on the flow differential pressure on both sides of choke. Three groups of correlations describing two-phase flow through wellhead chokes were examined. The first group involved simple empirical equations similar to those of Gilbert, the second group comprised derived equations of two-phase flow incorporating PVT properties, and third group is computational method. In the article we calculate the flow of oil and gas through choke with simulation of this two phase flow bye computational fluid dynamic method, we use Ansys- fluent for this simulation and finally compared results of computational simulation whit empirical equations, the results show good agreement between experimental and numerical results.

Keywords: CFD, two-phase, choke, critical

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Authors: J. K. Kapoor, Shagufta Jabin, H. S. Bhatia

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Polyamine flocculants were synthesized by poly-condensation of diphenylamine and epichlorohydrin using 1, 2-diaminoethane as modifying agent. The polyelectrolytes were prepared by taking epichlohydrin-diphenylamine in a molar ratio of 1:1, 1.5:1, 2:1, and 2.5:1. The flocculation performance of these polyelectrolytes was evaluated with rice industry waste water. The polyelectrolytes have been used in conjunction with alum for coagulation- flocculation process. Prior to the coagulation- flocculation process, air flotation technique was used with the aim to remove oil and grease content from waste water. Significant improvement was observed in the removal of oil and grease content after the air flotation technique. It has been able to remove 91.7% oil and grease from rice industry waste water. After coagulation-flocculation method, it has been observed that polyelectrolyte with epichlohydrin-diphenylamine molar ratio of 1.5:1 showed best results for the removal of pollutants from rice industry waste water. The highest efficiency of turbidity and TSS removal with polyelectrolyte has been found to be 97.5% and 98.2%, respectively. Results of these evaluations also reveal 86.8% removal of COD and 87.5% removal of BOD from rice industry waste water. Thus, we demonstrate optimization of coagulation–flocculation technique which is appropriate for waste water treatment.

Keywords: coagulation, flocculation, air flotation technique, polyelectrolyte, turbidity

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Authors: Mengke Zhan, Cheng-Gang Xie, Jian-Jun Shu

Abstract:

A venturi flowmeter is a common device used in multiphase flow rate measurement in the upstream oil and gas industry. Having a robust computational model for multiphase flow in a venturi is desirable for understanding the gas-liquid and fluid-pipe interactions and predicting pressure and phase distributions under various flow conditions. A steady Eulerian-Eulerian framework is used to simulate upward gas-liquid flow in a vertical venturi. The simulation results are compared with experimental measurements of venturi differential pressure and chord-averaged gas holdup in the venturi throat section. The choice of turbulence model is nontrivial in the multiphase flow modelling in a venturi. The performance cross-comparison of the k-ϵ model, Reynolds stress model (RSM) and shear-stress transport (SST) k-ω turbulence model is made in the study. In terms of accuracy and computational cost, the SST k-ω turbulence model is observed to be the most efficient.

Keywords: computational fluid dynamics (CFD), gas-liquid flow, turbulence modelling, venturi

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