**Commenced**in January 2007

**Frequency:**Monthly

**Edition:**International

**Paper Count:**356

# Search results for: void fraction.

##### 356 Gas-Liquid Two Phase Flow Phenomenon in Near Horizontal Upward and Downward Inclined Pipe Orientations

**Authors:**
Afshin J. Ghajar,
Swanand M. Bhagwat

**Abstract:**

The main purpose of this work is to experimentally investigate the effect of pipe orientation on two phase flow phenomenon. Flow pattern, void fraction and two phase pressure drop is measured in a polycarbonate pipe with an inside diameter of 12.7mm for inclination angles ranging from -20^{o} to +20^{o} using air-water fluid combination. The experimental data covers all flow patterns and the entire range of void fraction typically observed in two phase flow. The effect of pipe orientation on void fraction and two phase pressure drop is justified with reference to the change in flow structure and two phase flow behavior. In addition to this, the top performing void fraction and two phase pressure drop correlations available in the literature are presented and their performance is assessed against the experimental data in the present study and that available in the literature.

**Keywords:**
Flow patterns,
inclined two phase flow,
pressure drop,
void fraction.

##### 355 Transient Analysis of Central Region Void Fraction in a 3x3 Rod Bundle under Bubbly and Cap/Slug Flows

**Authors:**
Ya-Chi Yu,
Pei-Syuan Ruan,
Shao-Wen Chen,
Yu-Hsien Chang,
Jin-Der Lee,
Jong-Rong Wang,
Chunkuan Shih

**Abstract:**

_{f}=0.094 m/s), two different superficial air velocities (J

_{g}=0.094 m/s and 0.236 m/s) were tested and presented, which were corresponding to the flow conditions of bubbly flows and cap/slug flows, respectively. The time averaged central region void fraction was obtained as 0.109-0.122 with 0.028 standard deviation for the selected bubbly flow and 0.188-0.221with 0.101 standard deviation for the selected cap/slug flow, respectively. Through Fast Fourier Transform (FFT) analysis, no clear frequency peak was found in bubbly flow, while two dominant frequencies were identified around 1.6 Hz and 2.5 Hz in the present cap/slug flow.

**Keywords:**
Central region,
rod bundles,
transient void fraction,
two-phase flow.

##### 354 Analysis of Air-Water Two-Phase Flow in a 3x3 Rod Bundle

**Authors:**
Pei-Syuan Ruan,
Ya-Chi Yu,
Shao-Wen Chen,
Jin-Der Lee,
Jong-Rong Wang,
Chunkuan Shih

**Abstract:**

This study investigated the void fraction characteristics under low superficial gas velocity (J_{g}) and low superficial fluid velocity (J_{f}) conditions in a 3x3 rod bundle geometry. Three arrangements of conductivity probes were set to measure the void fraction at various cross-sectional regions, including rod-gap, sub-channel and rod-wall regions. The experimental tests were performed under the flow conditions of J_{g} = 0-0.236 m/s and J_{f} = 0-0.142 m/s, and the time-averaged void fractions were recorded at each flow condition. It was observed that while the superficial gas velocity increases, the small bubbles started to cluster together and become big bubbles. As the superficial fluid velocity increases, the local void fractions of the three test regions will get closer and the bubble distribution will be more uniform across the cross section.

**Keywords:**
Conductivity probes,
rod bundles,
two-phase flow,
void fraction.

##### 353 Experimental Investigation of Phase Distributions of Two-phase Air-silicone Oil Flow in a Vertical Pipe

**Authors:**
M. Abdulkadir,
V. Hernandez-Perez,
S. Sharaf,
I. S. Lowndes,
B. J. Azzopardi

**Abstract:**

**Keywords:**
WMS,
phase distribution,
silicone-oil,
riser

##### 352 Minimum Fluidization Velocities of Binary-Solid Mixtures: Model Comparison

**Authors:**
Mohammad Asif

**Abstract:**

**Keywords:**
Bed void fraction,
Binary solid mixture,
Minimumfluidization velocity,
Packing models

##### 351 Vapor Bubble Dynamics in Upward Subcooled Flow Boiling During Void Evolution

**Authors:**
Rouhollah Ahmadi,
Tatsuya Ueno,
Tomio Okawa

**Abstract:**

**Keywords:**
Subcooled flow boiling,
Bubble dynamics,
Void
fraction,
Sliding bubble.

##### 350 Hydrothermal Behavior of G-S Magnetically Stabilized Beds Consisting of Magnetic and Non-Magnetic Admixtures

**Authors:**
Z. Al-Qodah,
M. Al-Busoul,
A. Khraewish

**Abstract:**

**Keywords:**
Magnetic stabilization; Magnetic stabilized fluidizedbeds; Gas-fluidized beds.

##### 349 Computational Fluid Dynamics Modeling of Downward Bubbly Flows

**Authors:**
Mahmood Reza Rahimi,
Hajir Karimi

**Abstract:**

**Keywords:**
CFD,
Bubbly flow,
Vertical pipe,
Population
balance modeling,
Gas void fraction,
Liquid velocity,
Normal
turbulent stresses.

##### 348 Greedy Geographical Void Routing for Wireless Sensor Networks

**Authors:**
Chiang Tzu-Chiang,
Chang Jia-Lin,
Tsai Yue-Fu,
Li Sha-Pai

**Abstract:**

**Keywords:**
Wireless sensor network,
internet routing,
wireless network,
greedy void avoiding algorithm,
bypassing void.

##### 347 Slug Initiation Evaluation in Long Horizontal Channels Experimentally

**Authors:**
P. Adibi,
M. R. Ansari,
S. Jafari,
B. Habibpour,
E. Salimi

**Abstract:**

In this paper, the effect of gas and liquid superficial inlet velocities and for the first time the effect of liquid holdup on slug initiation position are studied experimentally. Empirical correlations are also presented based on the obtained results. The tests are conducted for three liquid holdups in a long horizontal channel with dimensions of 5cm10cm and 36m length. Usl and Usg rated as to 0.11m/s to 0.56m/s and 1.88m/s to 13m/s, respectively. The obtained results show that as αl=0.25, slug initiation position is increasing monotonically with Usl and Usg. During αl=0.50, slug initiation position is almost constant. For αl=0.75, slug initiation position is decreasing monotonically with Usl and Usg. In the case of equal void fraction of phases, generated slugs are weakly (low pressure). However, for the unequal void fraction of phases strong slugs (high pressure) are formed.

**Keywords:**
Liquid holdup,
Long horizontal channel,
Slug initiation position,
Superficial inlet velocity.

##### 346 Numerical Simulation of the Liquid-Vapor Interface Evolution with Material Properties

**Authors:**
Kimou Kouadio Prosper,
Souleymane Oumtanaga,
Tety Pierre,
Adou Kablan Jérôme

**Abstract:**

**Keywords:**
Two-fluid models,
homogeneous model,
interface,
averaged equations,
Jumps conditions,
void fraction.

##### 345 Simulation of Ammonia-Water Two Phase Flow in Bubble Pump

**Authors:**
Jemai Rabeb,
Benhmidene Ali,
Hidouri Khaoula,
Chaouachi Bechir

**Abstract:**

The diffusion-absorption refrigeration cycle consists of a generator bubble pump, an absorber, an evaporator and a condenser, and usually operates with ammonia/water/ hydrogen or helium as the working fluid. The aim of this paper is to study the stability problem a bubble pump. In fact instability can caused a reduction of bubble pump efficiency. To achieve this goal, we have simulated the behaviour of two-phase flow in a bubble pump by using a drift flow model. Equations of a drift flow model are formulated in the transitional regime, non-adiabatic condition and thermodynamic equilibrium between the liquid and vapour phases. Equations resolution allowed to define void fraction, and liquid and vapour velocities, as well as pressure and mixing enthalpy. Ammonia-water mixing is used as working fluid, where ammonia mass fraction in the inlet is 0.6. Present simulation is conducted out for a heating flux of 2 kW/m² to 5 kW/m² and bubble pump tube length of 1 m and 2.5 mm of inner diameter. Simulation results reveal oscillations of vapour and liquid velocities along time. Oscillations decrease with time and with heat flux. For sufficient time the steady state is established, it is characterised by constant liquid velocity and void fraction values. However, vapour velocity does not have the same behaviour, it increases for steady state too. On the other hand, pressure drop oscillations are studied.

**Keywords:**
Bubble pump,
drift flow model,
instability,
simulation.

##### 344 Effect of Curing Profile to Eliminate the Voids / Black Dots Formation in Underfill Epoxy for Hi-CTE Flip Chip Packaging

**Authors:**
Zainudin Kornain,
Azman Jalar,
Rozaidi Rasid,
Fong Chee Seng

**Abstract:**

**Keywords:**
black dots formation,
curing profile,
FC-CBGA,
underfill,
void formation,

##### 343 Electric Field Investigation in MV PILC Cables with Void Defect

**Authors:**
Mohamed A. Alsharif,
Peter A. Wallace,
Donald M. Hepburn,
Chengke Zhou

**Abstract:**

Worldwide, most PILC MV underground cables in use are approaching the end of their design life; hence, failures are likely to increase. This paper studies the electric field and potential distributions within the PILC insulted cable containing common void-defect. The finite element model of the performance of the belted PILC MV underground cable is presented. The variation of the electric field stress within the cable using the Finite Element Method (FEM) is concentrated. The effects of the void-defect within the insulation are given. Outcomes will lead to deeper understanding of the modeling of Paper Insulated Lead Covered (PILC) and electric field response of belted PILC insulted cable containing void defect.

**Keywords:**
MV PILC cables,
Finite Element Method /COMSOL
Multiphysics,
Electric Field Stress,
Partial Discharge Degradation.

##### 342 Two Fourth-order Iterative Methods Based on Continued Fraction for Root-finding Problems

**Authors:**
Shengfeng Li,
Rujing Wang

**Abstract:**

**Keywords:**
Iterative method,
Fixed-point iteration,
Thiele's continued
fraction,
Order of convergence.

##### 341 System Reduction Using Modified Pole Clustering and Modified Cauer Continued Fraction

**Authors:**
Jay Singh,
C. B. Vishwakarma,
Kalyan Chatterjee

**Abstract:**

A mixed method by combining modified pole clustering technique and modified cauer continued fraction is proposed for reducing the order of the large-scale dynamic systems. The denominator polynomial of the reduced order model is obtained by using modified pole clustering technique while the coefficients of the numerator are obtained by modified cauer continued fraction. This method generated 'k' number of reduced order models for kth order reduction. The superiority of the proposed method has been elaborated through numerical example taken from the literature and compared with few existing order reduction methods.

**Keywords:**
Modified Pole Clustering,
Modified Cauer
Continued Fraction,
Order Reduction,
Stability,
Transfer Function.

##### 340 The Magnetized Quantum Breathing in Cylindrical Dusty Plasma

**Authors:**
A. Abdikian

**Abstract:**

**Keywords:**
The linear quantum hydrodynamic model,
the magnetized quantum breathing mode,
the quantum dispersion relation of rotation mode,
void structure.

##### 339 Long-Term Durability of Roller-Compacted Concrete Pavement

**Authors:**
Jun Hee Lee,
Young Kyu Kim,
Seong Jae Hong,
Chamroeun Chhorn,
Seung Woo Lee

**Abstract:**

Roller-compacted concrete pavement (RCCP), an environmental friendly pavement of which load carry capacity benefitted from both hydration and aggregate interlock from roller compacting, demonstrated a superb structural performance for a relatively small amount of water and cement content. Even though an excellent structural performance can be secured, it is required to investigate roller-compacted concrete (RCC) under environmental loading and its long-term durability under critical conditions. In order to secure long-term durability, an appropriate internal air-void structure is required for this concrete. In this study, a method for improving the long-term durability of RCCP is suggested by analyzing the internal air-void structure and corresponding durability of RCC. The method of improving the long-term durability involves measurements of air content, air voids, and air-spacing factors in RCC that experiences changes in terms of type of air-entraining agent and its usage amount. This test is conducted according to the testing criteria in ASTM C 457, 672, and KS F 2456. It was found that the freezing-thawing and scaling resistances of RCC without any chemical admixture was quite low. Interestingly, an improvement of freezing-thawing and scaling resistances was observed for RCC with appropriate the air entraining (AE) agent content; Relative dynamic elastic modulus was found to be more than 80% for those mixtures. In RCC with AE agent mixtures, large amount of air was distributed within a range of 2% to 3%, and an air void spacing factor ranging between 200 and 300 μm (close to 250 μm, recommended by PCA) was secured. The long-term durability of RCC has a direct relationship with air-void spacing factor, and thus it can only be secured by ensuring the air void spacing factor through the inclusion of the AE in the mixture.

**Keywords:**
RCCP,
durability,
air spacing factor,
surface scaling resistance test,
freezing and thawing resistance test.

##### 338 Chemical Leaching of Metals from Landfill’s Fine Fraction

**Authors:**
E. Balkauskaitė,
A. Bučinskas,
R. Ivanauskas,
M. Kriipsalu,
G. Denafas

**Abstract:**

Leaching of heavy metals (chromium, zinc, copper) from the fine fraction of the Torma landfill (Estonia) was investigated. The leaching kinetics studies have determined the dependence of some metal’s concentration on the leaching time. Metals were leached with Aqua Regia, distilled water and EDTA (Ethylenediaminetetraacetic acid); process was most intensive 2 hours after the start of the experiment, except for copper with EDTA (0.5 h) and lead with EDTA (4 h). During leaching, steady concentrations of Fe, Mn, Cd and Pb were fully stabilized after 8 h; however concentrations of Cu and Ni were not stabilized after 10 h.

**Keywords:**
Landfills,
fine fraction,
leached metals,
leaching kinetics.

##### 337 Radiobiological Model in Radiotherapy Planning for Prostate Cancer Treatment

**Authors:**
Pradip Deb

**Abstract:**

**Keywords:**
Linear Quadratic Model,
TCP,
NTCP,
α/β ratio.

##### 336 Bose-Einstein Condensation in Neutral Many Bosonic System

**Authors:**
M. Al-Sugheir,
M. Sakhreya,
G. Alna'washi,
F. Al-Dweri

**Abstract:**

**Keywords:**
About four key words or phrases in alphabetical
order,
separated by commas

##### 335 The Use of Seashell by-Products in Pervious Concrete Pavers

**Authors:**
Dang Hanh Nguyen,
Nassim Sebaibi,
Mohamed Boutouil,
Lydia Leleyter,
Fabienne Baraud

**Abstract:**

Pervious concrete is a green alternative to conventional pavements with minimal fine aggregate and a high void content. Pervious concrete allows water to infiltrate through the pavement, thereby reducing the runoff and the requirement for stormwater management systems.

Seashell By-Products (SBP) are produced in an important quantity in France and are considered as waste. This work investigated to use SBP in pervious concrete and produce an even more environmentally friendly product, Pervious Concrete Pavers.

The research methodology involved substituting the coarse aggregate in the previous concrete mix design with 20%, 40% and 60% SBP. The testing showed that pervious concrete containing less than 40% SBP had strengths, permeability and void content which are comparable to the pervious concrete containing with only natural aggregate. The samples that contained 40% SBP or higher had a significant loss in strength and an increase in permeability and a void content from the control mix pervious concrete. On the basis of the results in this research, it was found that the natural aggregate can be substituted by SBP without affecting the delicate balance of a pervious concrete mix. Additional, it is recommended that the optimum replacement percentage for SBP in pervious concrete is 40 % direct replacement of natural coarse aggregate while maintaining the structural performance and drainage capabilities of the pervious concrete.

**Keywords:**
Seashell by-products,
pervious concrete pavers,
permeability and mechanical strength.

##### 334 The Influence of Fiber Volume Fraction on Thermal Conductivity of Pultruded Profile

**Authors:**
V. Lukášová,
P. Peukert,
V. Votrubec

**Abstract:**

**Keywords:**
Numerical simulation,
pultruded profile,
volume fraction,
thermal conductivity.

##### 333 A Numerical Study of the Effect of Side-Dump Angle on Fuel Droplets Sizing in a Three- Dimensional Side-Dump Combustor

**Authors:**
M. Mojtahedpoor,
M. M. Doustdar

**Abstract:**

**Keywords:**
Side-Dump combustor,
Droplets sizing,
Side-Dump
angle,
KIVA-3V

##### 332 A Novel Approach for Beneficiation and Dewatering of Coal Fines for Indian Coal Preparation Plant

**Authors:**
K.K. Sharma,
K.M.K. Sinha,
T.G. Charan,
D.D. Haldar

**Abstract:**

**Keywords:**
coal fines,
dewatering,
environment,
flotation,
oleoflotation,
spiral

##### 331 A Wall Law for Two-Phase Turbulent Boundary Layers

**Authors:**
Dhahri Maher,
Aouinet Hana

**Abstract:**

**Keywords:**
Bubbly flows,
log law,
boundary layer.

##### 330 Periodic Mixed Convection of a Nanofluid in a Cavity with Top Lid Sinusoidal Motion

**Authors:**
Arash Karimipour,
M. Afrand,
M. M. Bazofti

**Abstract:**

**Keywords:**
Nanofluid,
Top lid oscillation,
Mixed convection,
Volume fraction

##### 329 Effect of Modeling of Hydraulic Form Loss Coefficient to Break on Emergency Core Coolant Bypass

**Authors:**
Young S. Bang,
Dong H. Yoon,
Seung H. Yoo

**Abstract:**

Emergency Core Coolant Bypass (ECC Bypass) has been regarded as an important phenomenon to peak cladding temperature of large-break loss-of-coolant-accidents (LBLOCA) in nuclear power plants (NPP). A modeling scheme to address the ECC Bypass phenomena and the calculation of LBLOCA using that scheme are discussed in the present paper. A hydraulic form loss coefficient (HFLC) from the reactor vessel downcomer to the broken cold leg is predicted by the computational fluid dynamics (CFD) code with a variation of the void fraction incoming from the downcomer. The maximum, mean, and minimum values of FLC are derived from the CFD results and are incorporated into the LBLOCA calculation using a system thermal-hydraulic code, MARS-KS. As a relevant parameter addressing the ECC Bypass phenomena, the FLC to the break and its range are proposed.

**Keywords:**
CFD analysis,
ECC Bypass,
hydraulic form loss coefficient,
system thermal-hydraulic code.

##### 328 One Dimensional Reactor Modeling for Methanol Steam Reforming to Hydrogen

**Authors:**
Hongfang Ma,
Mingchuan Zhou,
Haitao Zhang,
Weiyong Ying

**Abstract:**

One dimensional pseudo-homogenous modeling has been performed for methanol steam reforming reactor. The results show that the models can well predict the industrial data. The reactor had minimum temperature along axial because of endothermic reaction. Hydrogen productions and temperature profiles along axial were investigated regarding operation conditions such as inlet mass flow rate and mass fraction of methanol, inlet temperature of external thermal oil. Low inlet mass flow rate of methanol, low inlet temperature, and high mass fraction of methanol decreased minimum temperature along axial. Low inlet mass flow rate of methanol, high mass fraction of methanol, and high inlet temperature of thermal oil made cold point forward. Low mass fraction, high mass flow rate, and high inlet temperature of thermal oil increased hydrogen production. One dimensional models can be a guide for industrial operation.

**Keywords:**
Reactor,
modeling,
methanol,
steam reforming.

##### 327 The Incorporation of In in GaAsN as a Means of N Fraction Calibration

**Authors:**
H. Hashim,
B. F. Usher

**Abstract:**

**Keywords:**
Indium,
molecular beam epitaxy,
nitrogen,
straincancellation.