Vol.16, No.2, 2020-Table of Contents
  • MHD Flow and Nonlinear Thermal Radiative Heat Transfer of Dusty Prandtl Fluid over a Stretching Sheet
  • Abstract Boundary layer flows and melting heat transfer of a Prandtl fluid over a stretching surface in the presence of fluid particle suspensions has been investigated. The converted set of boundary layer equations are solved numerically by RKF-45 method. Obtained numerical results for flow and heat transfer characteristics are deliberated for various physical parameters. Furthermore, the skin friction coefficient and Nusselt number are also presented in Tabs. 2 and 3. It is found that the heat transfer rates are advanced in occurrence of nonlinear radiation compered to linear radiation. Also, it is noticed that velocity and temperature profile increases by increasing… More
  •   Views:222       Downloads:222        Download PDF
  • Pressure-Driven Gas Flows in Micro Channels with a Slip Boundary: A Numerical Investigation
  • Abstract In this paper, flow of slightly rarefied compressible nitrogen in microchannels has been investigated numerically for low values of Reynolds and Mach numbers. The 2D governing equations were solved using Finite Element Method with first-order slip boundary conditions (Comsol Multiphysics software). A validation was performed by comparing with similar configuration from the literature. It was found that our model can accurately predict the pressure driven flow in microchannels. Several interesting findings are reported about the Relative pressure, longitudinal velocity, Mach number, effect of gas rarefaction and flow rate. More
  •   Views:765       Downloads:169        Download PDF
  • Influence of Tip Clearance on Unsteady Flow in Automobile Engine Pump
  • Abstract The automobile engine pump is an important part of the automobile cooling system, and has a direct influence on the engine performance. Based on the SST k-ω turbulence model, unsteady numerical simulation for an automobile engine pump with different tip clearances was carried out by Fluent. To study the flow field characteristics and pressure fluctuation, the characteristics of secondary flow distribution in volute are also analyzed. The result shows that the pressure fluctuation characteristics of the flow field show obvious periodic variation at different levels of tip clearances. The peak value of pressure fluctuation at each monitoring point is dependent… More
  •   Views:178       Downloads:147        Download PDF
  • Analysis of the Influence of Viscosity and Thermal Conductivity on Heat Transfer by Al2O3-Water Nanofluid
  • Abstract The addition of nanoparticles into liquid, even at low concentrations, leads to an increase in both, dynamic viscosity and thermal conductivity. Furthermore, the increase in temperature causes an increase in thermal conductivity and a decrease in the nanofluid viscosity. In this context, a numerical investigation of the competition between viscosity and thermal conductivity about their effects on heat transfer by Al2O3-water nanofluid was conducted. A numerical study of heat transfer in a square cavity, filled with Al2O3-water nanofluid and heated from the left side, was presented in this paper. Continuity, momentum, and thermal energy equations are solved by the finite… More
  •   Views:174       Downloads:143        Download PDF
  • Fluid Flow and Convective Heat Transfer in a Water Chemical Condenser
  • Abstract In this paper, a detailed investigation of water (Pr ¼ 7:0) convection in a chemical condenser is carried out. Two openings are located along one side of the cavity. The Navier-Stokes equations are solved in the frame of a control volume method using the SIMPLEC algorithm to implement adequate coupling of pressure and velocity. Special emphasis is given to the influence of the Reynolds number, the tilt of the channel and the Rayleigh number on the convective heat transfer. Results are presented and discussed allowing the control parameters to span relatively wide intervals: Rayleigh number (104 ≤ Ra ≤ 5… More
  •   Views:180       Downloads:150        Download PDF
  • Design and Experiment-Based Optimization of High-Flow Hydraulic One-Way Valves
  • Abstract High-flow hydraulic one-way valves in water pipes are typically used to mitigate conditions, which would otherwise cause vibration and cavitation erosion after long-term operation. To prevent cavitation and enhance the performance of hydraulic one-way valves, in the present work a dedicated experimental study has been conducted. The structural parameters relating to the pilot valve core, the main valve core, and the through-flow section of the considered flow channel have been changed to analyse reverse impact, and cavitation, characteristics. The results show that the control pressure has a weak effect on the cavitation characteristics, while changes in the structural parameters can… More
  •   Views:158       Downloads:129        Download PDF
  • Determination of a Safe Distance for Atomic Hydrogen Depositions in Hot-Wire Chemical Vapour Deposition by Means of CFD Heat Transfer Simulations
  • Abstract A heat transfer study was conducted, in the framework of Computational Fluid Dynamics (CFD), on a Hot-Wire Chemical Vapour Deposition (HWCVD) reactor chamber to determine a safe deposition distance for atomic hydrogen produced by HWCVD. The objective of this study was to show the feasibility of using heat transfer simulations in determining a safe deposition distance for deposition of this kind. All CFD simulations were set-up and solved within the framework of the CFD packages of OpenFOAM namely; snappyHexMesh for mesh generation, buoyantSimpleFoam and rhoSimpleFoam as the solvers and paraView as the post-processing tool. Using a standard set of deposition… More
  •   Views:183       Downloads:168        Download PDF
  • Numerical Fluid Flow Modelling in Multiple Fractured Porous Reservoirs
  • Abstract This paper compares the fluid flow phenomena occurring within a fractured reservoir for three different fracture models using computational fluid dynamics. The effect of the fracture-matrix interface condition is studied on the pressure and velocity distribution. The fracture models were compared based on the variation in pressure and permeability conditions. The model was developed for isotropic and anisotropic permeability conditions. The results suggest that the fracture aperture can have a drastic effect on fluid flow. The porous fracture-matrix interface condition produces more realistic transport of fluids. By increasing the permeability in the isotropic porous matrix, the pressure drop was significantly… More
  •   Views:249       Downloads:147        Download PDF
  • Heat and Mass Transfer Characteristics of Alkali Metals in a Combined Wick of High-Temperature Heat Pipe
  • Abstract To study the heat and mass transfer characteristics of alkali metals in a combined porous wick in high-temperature heat pipes, a three-dimensional (3-D) numerical model is constructed by using the finite volume method, Darcy’s theory, and the theory of local thermal equilibrium. The research finds that the pressure drop of fluids flowing through a combined porous wick exhibits an increasing trend with increasing flow velocity at the inlet and with decreasing permeability of the porous media; a combined porous wick of lower porosity and permeability and larger fluid velocity at the inlet is found to have a less uniformly distributed… More
  •   Views:172       Downloads:145        Download PDF
  • Numerical Modelling of Proppant Transport in Hydraulic Fractures
  • Abstract The distribution of proppant injected in hydraulic fractures significantly affects the fracture conductivity and well performance. The proppant transport in thin fracturing fluid used during hydraulic fracturing in the unconventional reservoirs is considerably different from fracturing fluids in the conventional reservoir due to the very low viscosity and quick deposition of the proppants. This paper presents the development of a threedimensional Computational Fluid Dynamics (CFD) modelling technique for the prediction of proppant-fluid multiphase flow in hydraulic fractures. The proposed model also simulates the fluid leak-off behaviour from the fracture wall. The Euler-Granular and CFD-Discrete Element Method (CFD-DEM) multiphase modelling approach… More
  •   Views:187       Downloads:153        Download PDF
  • Study on Dynamic Prediction of Two-Phase Pipe Flow in Inclined Wellbore with Middle and High Yield
  • Abstract Gas-liquid two-phase flow is ubiquitous in the process of oil and gas exploitation, gathering and transportation. Flow pattern, liquid holdup and pressure drop are important parameters in the process of gas-liquid two-phase flow, which are closely related to the smooth passage of the two-phase fluid in the pipe section. Although Mukherjee, Barnea and others have studied the conventional viscous gas-liquid two-phase flow for a long time at home and abroad, the overall experimental scope is not comprehensive enough and the early experimental conditions are limited. Therefore, there is still a lack of systematic experimental research and wellbore pressure for gas-liquid… More
  •   Views:211       Downloads:151        Download PDF
  • On the Liquid-Vapor Phase-Change Interface Conditions for Numerical Simulation of Violent Separated Flows
  • Abstract Numerous models have been proposed in the literature to include phase change into numerical simulations of two-phase flows. This review paper presents the modeling options that have been taken in order to obtain a model for violent separated flows with application to sloshing wave impacts. A relaxation model based on linear non-equilibrium thermodynamics has been chosen to compute the rate of phase change. The integration in the system of partial differential equations is done through a non-conservative advection term. For each of these modelling choices, some alternative models from the literature are presented and discussed. The theoretical framework for all… More
  •   Views:203       Downloads:152        Download PDF
  • Linear and Nonlinear Stability Analysis in Microfluidic Systems
  • Abstract In this article we use analytical and numerical modeling to describe parallel viscous two-phase flows in microchannels. The focus is on idealized two-dimensional geometries, with a view to validating the various methodologies for future work in three dimensions. In the first instance, we use analytical Orr-Sommerfeld theory to describe the linear instability which governs the formation of small-amplitude waves in such systems. We then compare the results of this analysis with an in-house Computational Fluid Dynamics (CFD) solver called TPLS. Excellent agreement between the theoretical analysis and TPLS is obtained in the regime of small-amplitude waves. We continue the numerical… More
  •   Views:184       Downloads:174        Download PDF