**Commenced**in January 2007

**Frequency:**Monthly

**Edition:**International

**Paper Count:**21

# Search results for: rectangular channel

##### 21 Modified Hybrid Genetic Algorithm-Based Artificial Neural Network Application on Wall Shear Stress Prediction

**Authors:**
Zohreh Sheikh Khozani,
Wan Hanna Melini Wan Mohtar,
Mojtaba Porhemmat

**Abstract:**

Prediction of wall shear stress in a rectangular channel, with non-homogeneous roughness distribution, was studied. Estimation of shear stress is an important subject in hydraulic engineering, since it affects the flow structure directly. In this study, the Genetic Algorithm Artificial (GAA) neural network is introduced as a hybrid methodology of the Artificial Neural Network (ANN) and modified Genetic Algorithm (GA) combination. This GAA method was employed to predict the wall shear stress. Various input combinations and transfer functions were considered to find the most appropriate GAA model. The results show that the proposed GAA method could predict the wall shear stress of open channels with high accuracy, by Root Mean Square Error (RMSE) of 0.064 in the test dataset. Thus, using GAA provides an accurate and practical simple-to-use equation.

**Keywords:**
Artificial neural network,
genetic algorithm,
genetic programming,
rectangular channel,
shear stress.

##### 20 Steady State Natural Convection in Vertical Heated Rectangular Channel between Two Vertical Parallel MTR-Type Fuel Plates

**Authors:**
Djalal Hamed

**Abstract:**

**Keywords:**
Buoyancy force,
friction force,
friction factor,
MTR-type fuel,
natural convection,
vertical heated rectangular channel.

##### 19 Thermal Hydraulic Analysis of the IAEA 10MW Benchmark Reactor under Normal Operating Condition

**Authors:**
Hamed Djalal

**Abstract:**

The aim of this paper is to perform a thermal-hydraulic analysis of the IAEA 10 MW benchmark reactor solving analytically and numerically, by mean of the finite volume method, respectively the steady state and transient forced convection in rectangular narrow channel between two parallel MTR-type fuel plates, imposed under a cosine shape heat flux. A comparison between both solutions is presented to determine the minimal coolant velocity which can ensure a safe reactor core cooling, where the cladding temperature should not reach a specific safety limit 90 °C. For this purpose, a computer program is developed to determine the principal parameter related to the nuclear core safety, such as the temperature distribution in the fuel plate and in the coolant (light water) as a function of the inlet coolant velocity. Finally, a good agreement is noticed between the both analytical and numerical solutions, where the obtained results are displayed graphically.

**Keywords:**
Forced convection,
friction factor pressure drop thermal hydraulic analysis,
vertical heated rectangular channel.

##### 18 Numerical Solution of Transient Natural Convection in Vertical Heated Rectangular Channel between Two Vertical Parallel MTR-Type Fuel Plates

**Authors:**
Djalal Hamed

**Abstract:**

The aim of this paper is to perform, by mean of the finite volume method, a numerical solution of the transient natural convection in a narrow rectangular channel between two vertical parallel Material Testing Reactor (MTR)-type fuel plates, imposed under a heat flux with a cosine shape to determine the margin of the nuclear core power at which the natural convection cooling mode can ensure a safe core cooling, where the cladding temperature should not reach a specific safety limits (90 °C). For this purpose, a computer program is developed to determine the principal parameters related to the nuclear core safety, such as the temperature distribution in the fuel plate and in the coolant (light water) as a function of the reactor core power. Throughout the obtained results, we noticed that the core power should not reach 400 kW, to ensure a safe passive residual heat removing from the nuclear core by the upward natural convection cooling mode.

**Keywords:**
Buoyancy force,
friction force,
friction factor,
finite volume method,
transient natural convection,
thermal hydraulic analysis,
vertical heated rectangular channel.

##### 17 Analytical Formulae for the Approach Velocity Head Coefficient

**Authors:**
Abdulrahman Abdulrahman

**Abstract:**

Critical depth meters, such as abroad crested weir, Venture Flume and combined control flume are standard devices for measuring flow in open channels. The discharge relation for these devices cannot be solved directly, but it needs iteration process to account for the approach velocity head. In this paper, analytical solution was developed to calculate the discharge in a combined critical depth-meter namely, a hump combined with lateral contraction in rectangular channel with subcritical approach flow including energy losses. Also analytical formulae were derived for approach velocity head coefficient for different types of critical depth meters. The solution was derived by solving a standard cubic equation considering energy loss on the base of trigonometric identity. The advantage of this technique is to avoid iteration process adopted in measuring flow by these devices. Numerical examples are chosen for demonstration of the proposed solution.

**Keywords:**
Broad crested weir,
combined control meter,
control structures,
critical flow,
discharge measurement,
flow control,
hydraulic engineering,
hydraulic structures,
open channel flow.

##### 16 Numerical Solution of Manning's Equation in Rectangular Channels

**Authors:**
Abdulrahman Abdulrahman

**Abstract:**

**Keywords:**
Channel design,
civil engineering,
hydraulic engineering,
open channel flow,
Manning's equation,
normal depth,
uniform flow.

##### 15 Parametric and Analysis Study of the Melting in Slabs Heated by a Laminar Heat Transfer Fluid in Downward and Upward Flows

**Authors:**
Radouane Elbahjaoui,
Hamid El Qarnia

**Abstract:**

The present work aims to investigate numerically the thermal and flow characteristics of a rectangular latent heat storage unit (LHSU) during the melting process of a phase change material (PCM). The LHSU consists of a number of vertical and identical plates of PCM separated by rectangular channels. The melting process is initiated when the LHSU is heated by a heat transfer fluid (HTF: water) flowing in channels in a downward or upward direction. The proposed study is motivated by the need to optimize the thermal performance of the LHSU by accelerating the charging process. A mathematical model is developed and a fixed-grid enthalpy formulation is adopted for modeling the melting process coupling with convection-conduction heat transfer. The finite volume method was used for discretization. The obtained numerical results are compared with experimental, analytical and numerical ones found in the literature and reasonable agreement is obtained. Thereafter, the numerical investigations were carried out to highlight the effects of the HTF flow direction and the aspect ratio of the PCM slabs on the heat transfer characteristics and thermal performance enhancement of the LHSU.

**Keywords:**
Phase change material,
thermal energy storage,
latent heat storage unit,
melting.

##### 14 Numerical Analysis of the Melting of Nano-Enhanced Phase Change Material in a Rectangular Latent Heat Storage Unit

**Authors:**
Radouane Elbahjaoui,
Hamid El Qarnia

**Abstract:**

_{2}O

_{3 }nanoparticles in a rectangular latent heat storage unit (LHSU) is numerically investigated. The storage unit consists of a number of vertical and identical plates of nano-enhanced phase change material (NEPCM) separated by rectangular channels in which heat transfer fluid flows (HTF: Water). A two dimensional mathematical model is considered to investigate numerically the heat and flow characteristics of the LHSU. The melting problem was formulated using the enthalpy porosity method. The finite volume approach was used for solving equations. The effects of nanoparticles’ volumetric fraction and the Reynolds number on the thermal performance of the storage unit were investigated.

**Keywords:**
Nano-enhanced phase change material,
phase change material,
nanoparticles,
latent heat storage unit,
melting.

##### 13 Analysis of Three-Dimensional Longitudinal Rolls Induced by Double Diffusive Poiseuille-Rayleigh-Benard Flows in Rectangular Channels

**Authors:**
O. Rahli,
N. Mimouni,
R. Bennacer,
K. Bouhadef

**Abstract:**

**Keywords:**
Heat and mass transfer,
mixed convection,
Poiseuille-Rayleigh-Benard flow,
rectangular duct.

##### 12 Localized and Time-Resolved Velocity Measurements of Pulsatile Flow in a Rectangular Channel

**Authors:**
R. Blythman,
N. Jeffers,
T. Persoons,
D. B. Murray

**Abstract:**

**Keywords:**
Heat transfer enhancement,
particle image
velocimetry,
localized and time-resolved velocity,
photonics
and electronics cooling,
pulsating flow,
Richardson’s annular effect.

##### 11 Contribution to Experiments of a Free Surface Supercritical Flow over an Uneven Bottom

**Authors:**
M. Bougamouza,
M. Bouhadef,
T. Zitoun

**Abstract:**

**Keywords:**
Experiments,
free-surface flow,
hydraulic channel,
uneven bottom,
laser anemometry,
supercritical regime.

##### 10 Numerical Investigation of Heat Transfer in a Channel with Delta Winglet Vortex Generators at Different Reynolds Numbers

**Authors:**
N. K. Singh

**Abstract:**

In this study the augmentation of heat transfer in a rectangular channel with triangular vortex generators is evaluated. The span wise averaged Nusselt number, mean temperature and total heat flux are compared with and without vortex generators in the channel at a blade angle of 30° for Reynolds numbers 800, 1200, 1600, and 2000. The use of vortex generators increases the span wise averaged Nusselt number compared to the case without vortex generators considerably. At a particular blade angle, increasing the Reynolds number results in an enhancement in the overall performance and span wise averaged Nusselt number was found to be greater at particular location for larger Reynolds number. The total heat flux from the bottom wall with vortex generators was found to be greater than that without vortex generators and the difference increases with increase in Reynolds number.

**Keywords:**
Heat transfer,
channel with vortex generators,
numerical simulation,
effect of Reynolds number on heat transfer.

##### 9 Finite Element Prediction of Multi-Size Particulate Flow through Two-Dimensional Pump Casing

**Authors:**
K. V. Pagalthivarthi,
R. J. Visintainer

**Abstract:**

Two-dimensional Eulerian (volume-averaged) continuity and momentum equations governing multi-size slurry flow through pump casings are solved by applying a penalty finite element formulation. The computational strategy validated for multi-phase flow through rectangular channels is adapted to the present study. The flow fields of the carrier, mixture and each solids species, and the concentration field of each species are determined sequentially in an iterative manner. The eddy viscosity field computed using Spalart-Allmaras model for the pure carrier phase is modified for the presence of particles. Streamline upwind Petrov-Galerkin formulation is used for all the momentum equations for the carrier, mixture and each solids species and the concentration field for each species. After ensuring mesh-independence of solutions, results of multi-size particulate flow simulation are presented to bring out the effect of bulk flow rate, average inlet concentration, and inlet particle size distribution. Mono-size computations using (1) the concentration-weighted mean diameter of the slurry and (2) the D50 size of the slurry are also presented for comparison with multi-size results.

**Keywords:**
Eulerian-Eulerian model,
Multi-size particulate flow,
Penalty finite elements,
Pump casing,
Spalart-Allmaras.

##### 8 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.

##### 7 Analytical Solutions of Three Dimensional Steady-State Heat Transfer in Rectangular Ribs

**Authors:**
Tao Nie,
Weiqiang Liu

**Abstract:**

**Keywords:**
variable separation method,
analytical solution,
rib,
heat transfer

##### 6 Heat Transfer Analysis of Rectangular Channel Plate Heat Sink

**Authors:**
Zhang Lei,
Liu Min,
Liu Botao

**Abstract:**

**Keywords:**
heat transfer,
heat sink,
numerical simulation

##### 5 Simulation of 3D Flow using Numerical Model at Open-channel Confluences

**Authors:**
R.Goudarzizadeh,
S.H.Mousavi Jahromi,
N.Hedayat

**Abstract:**

**Keywords:**
900 confluence angle,
flow separation zone,
numerical modeling,
turbulent flow.

##### 4 High Performance Computing Using Out-of- Core Sparse Direct Solvers

**Authors:**
Mandhapati P. Raju,
Siddhartha Khaitan

**Abstract:**

**Keywords:**
Out-of-core,
PARDISO,
MUMPS,
Newton.

##### 3 Heat Transfer and Frictional Characteristics in Rectangular Channel with Inclined Perforated Baffles

**Authors:**
Se Kyung Oh,
Ary Bachtiar Krishna Putra,
Soo Whan Ahn

**Abstract:**

**Keywords:**
Turbulent flow,
rectangular channel,
inclined baffle,
heat transfer,
friction factor.

##### 2 Experimental Study on Gas-Viscous Liquid Mixture Flow Regimes and Transitions Criteria in Vertical Narrow Rectangular Channels

**Authors:**
F. J. Sowiński,
M. Dziubiński

**Abstract:**

In the study the influence of the physical-chemical properties of a liquid, the width of a channel gap and the superficial liquid and gas velocities on the patterns formed during two phase flows in vertical, narrow mini-channels was investigated. The research was performed in the channels of rectangular cross-section and of dimensions: 15 x 0.65 mm and 7.5 x 0.73 mm. The experimental data were compared with the published criteria of the transitions between the patterns of two-phase flows.

**Keywords:**
Two-phase flow,
flow regimes,
mini-channel,
viscosity.

##### 1 Electroviscous Effects in Low Reynolds Number Flow through a Microfluidic Contraction with Rectangular Cross-Section

**Authors:**
Malcolm R Davidson,
Ram P. Bharti,
Petar Liovic,
Dalton J.E. Harvie

**Abstract:**

**Keywords:**
Contraction,
Electroviscous,
Microfluidic,
Numerical.