C. S. Nor Azwadi

THREE-DIMENSIONAL THERMAL LATTICE BOLTZMANN SIMULATION OF NATURAL CONVECTION IN A CUBIC CAVITY

In this paper, a three-dimensional (3D) thermal lattice Boltzmann model is proposed to simulate 3D incompressible thermal flow problem. Our model is based on the double-distribution function approach. We found that a new and simple lattice type of eight-velocity model for the internal energy density distribution function can be developed, where the viscous and compressive heating effects are negligible. Numerical results of 3D natural convection flow in a cubic cavity are presented.

Simplified finite difference thermal lattice Boltzmann method

In this paper, a well-known finite difference technique is combined with thermal lattice Boltzmann method to solve 2-dimensional incompressible thermal fluid flow problems. A small number of microvelocity components are applied for the calculation of temperature field. The combination of finite difference with lattice Boltzmann method is found to be an efficient and stable approach for the simulation at high Rayleigh number of natural convection in a square cavity.

Simulation of Mixed Convection around a Square by Using LBM

Laminar natural heat transfer in the horizontal channel with a heated square cylinder has been studied by using lattice Boltzmann method. Air and water are applied as fluid flow and the walls of channel are adiabatic. Lattice Boltzmann method (LBM) as one of stochastic methods has been used to study the hydrodynamic and thermal behaviours of water and air, with Prantle number 7.01 and 0.71, respectively. Velocity and temperature profiles are achieved near each surface of the square. The results show relation between Prantle number and symmetric degree of streamlines and isotherms profile

Effect of Addition of Tertiary-Butyl Hydroquinone into Palm Oil to Reduce Wear and Friction Using Four-Ball Tribotester

ABSTRACT Replacing mineral oil with vegetable oils as lubricants continues to attract interest due to their environmentally friendly characteristics and ease of disposal. However, one disadvantage can be low thermal oxidative stability. The purpose of our research is to investigate the ways in which oxidation can be contained by combining palm oil with a phenolic antioxidant. A homogeneous mix of palm oil and tertiary-butyl hydroquinone was found to exhibit satisfactory antioxidant properties and reduce wear and friction. Superior mineral engine oil was used to benchmark the performance.

Numerical Prediction of Heat Transfer from Heated Thin Plate in a Square Cavity by Using LBM

In this paper, natural convection heat transfer from heated plate positioned in square cavity vertically and horizontally was studied. Thermal BGK lattice Boltzmann numerical scheme was applied. The simulation was launched for different aspect ratio A=0.4 and 0.6 at Grasshof numbers and . Air was chosen as working fluid (Pr=0.71). Good arrangement was obtained between the present work and pervious approach using finite volume method. It is found that convection upper side of plate is increase as Grasshof number is increased.

Numerical Analysis on the Effects of Cavity Geometry with Heat towards Contaminant Removal

Contaminants are recently discovered at the joint of large piping system and causing defect to industrial product. A computational analysis can be used as a solution of the hydrodynamic contaminant removal without any modification needed. In this paper, the effect of heat is introduced to analyze the heat transfer and flow field in a channel with cavity heated at the bottom sides coupled with different shape of cavity. The cavity shape used comes with three shapes i.e. square, triangle and semicircle. The process of fluid dynamic in a cavity is modeled via numerical solution of the NavierStokes equations using Cubic Interpolated Profile (CIP) method. By using the simulation of hydrodynamic contaminant removal, the flow of streamlines and vortices pattern was investigated in the cavities. In order to remove all of the contaminant, hydrodynamic need to take part in this simulation which is flow from the inlet of the channel and create vortices to remove it from the cavities. The result shows that the percentage of contaminant removal is higher for semicircle cavity with higher Grashof number. The result also indicates that vortices formation is highly dependent on the cavity geometry and creates a buoyancy effect.

Regularized Lattice Boltzmann Simulation of Laminar Natural Convection in Entrance Region of 2D Channels

This paper presents a numerical study of incompressible laminar natural convection in entrance region of two dimensional vertical and inclined channels using regularized lattice Boltzmann Bhatnaghar-Gross-Krook method. Individual distribution functions with lattice types D2Q9 and D2Q5 are considered to solve fluid flow and thermal fields, respectively. Rayleigh number and inclination angle are varied from 10e2 to 10e6 and 0 to 60°, respectively. Distribution functions are introduced to mimic Bernoulli’s equation for calculating pressure at the inlet. Predicted Nusselt numbers are compared with Nusselt numbers correlation. Averaged Nusselt numbers compare well with Nusselt number correlation of Bar-Cohen & Rohsenow.

The effect of different aspect ratio and bottom heat flux towards contaminant removal using numerical analysis

Cubic Interpolated Pseudo-particle (CIP) numerical simulation scheme has been anticipated to predict the interaction involving fluids and solid particles in an open channel with rectangular shaped cavity flow. The rectangular shaped cavity is looking by different aspect ratio in modelling the real pipeline joints that are in a range of sizes. Various inlet velocities are also being applied in predicting various fluid flow characteristics. In this paper, the constant heat flux is introduced at the bottom wall, showing the buoyancy effects towards the contaminants removal rate. In order to characterize the fluid flow, the numerical scheme alone is initially tested and validated in a lid driven cavity with a single particle. The study of buoyancy effects and different aspect ratio of rectangular geometry were carried out using a MATLAB govern by Navier-Stokes equation. CIP is used as a model for a numerical scheme solver for fluid solid particles interaction. The result shows that the higher aspect ratio coupled with heated bottom wall give higher percentage of contaminants removal rate. Comparing with the benchmark results has demonstrated the applicability of the method to reproduce fluid structure which is complex in the system. Despite a slight deviation of the formations of vortices from some of the literature results, the general pattern is considered to be in close agreement with those published in the literature.

Cubic-Interpolated-Pseudo-Particle Method to predict dynamic behaviour of fluid in shear driven cavity

In this paper, Cubic Interpolated Pseudo Particle Method is proposed to investigate the dynamic behavior of fluid motion in shear lid-driven cavity. The CIP scheme is individually performed to observe the behavior of the fluid motion at varying Reynolds numbers of 100, 400 and 1000. Comparison of the achieved results with the experimental results approves the capability of CIP to establish the sophistication of fluid structure in the system. Although the achieved trajectory had slightly difference but it was almost following the same pattern published in the literatures. The most advantage of this method is that it aims to accelerate processing time as well as higher exponent of accuracy.

Simulation of Natural Convection Heat Transfer in an Inclined Square Cavity With Perfectly Conducting Side Walls Using Finite Difference Approach

This study is about numerical simulation of natural heat transfer inside an inclined square cavity with perfectly conducting boundary conditions for the side walls. The Navier Stokes equations were solved using finite difference approach with uniform mesh procedure. Three different inclination angels were applied and the results are presented in terms of streamlines and isotherms plots. Based on the fluid flow pattern and the isothermal lines behaviour, the convection heat transfer has shown domination over the conduction as the tilt angle increases. The simulation of natural convection inside an air filled‐tilted cavity is the first time to be done to the best of our knowledge.