Ahmed A.A. Attia

Computational Investigations of Thermal Simulation of Shell and Tube Heat Exchanger

In the present paper, simulation for shell and tube heat exchanger investigated using CFD techniques. Numerical simulations of the turbulent, three-dimensional fluid flow and heat transfer are performed using Ansys Fluent 6.3. The effect of friction characteristics on the model of heat exchanger is discussed. A RNG κ-e turbulence model with non-equilibrium wall function and 2nd order upwind is used. The present model is validated with the experimental literature and show a good agreement. The numerical results of the present study predict reasonably agree well with available correlations. Finally the present study model can be used to model a shell and tube heat exchanger with a satisfactory accuracy level in predictions.Copyright

Simulation of Diffuser Augmented Wind Turbine performance

The main objective of this research is to optimize the diffuser design of Diffuser Augmented Wind Turbine (DAWT). Specifically, this study investigates the effect of different shapes of diffusers to develop the suitable diffuser parameter for the wind turbine power enhancement. For that purpose, two diffuser cases have been recommended as an effective design in increasing wind speed, using a validated model of a small commercial wind turbine (AMPAIR-300) in it were developed and each case is simulated and analyzed using design software Solid-works and Computational Fluid Dynamic (CFD) software Fluent-ANSYS-15, As per the study, for diffuser case-1,the diffuser splitter degrades the diffuser effect when its open angle higher than the diffuser open angle, for diffuser case-2 the diffuser splitter enhance the diffuser effect when its open angle lower than diffuser open angle, also adding inlet shroud directs the wind flow into the inlet of diffuser and the diffuser flange effect on the power enhancement was significant and also its induced axial load was significant, and it is recommended to study the optimum dimension of inlet shroud, diffuser flange and diffuser splitter to minimize the coefficient of thrust and to enhance the coefficient of power.

On the Computations of Thermal Behaviour of Shell and Tube Heat Exchanger

A numerical investigation for shell and tube heat exchanger using Fluent commercial package to build a reliable model for simulating the heat transfer and friction characteristics of heat exchangers, the model were validated with the literature and show a good agreement which result that this model can be accounted as a good CFD model for heat exchanger simulation, and a conclusion was driven that RNG κ-e model with nonequilibrium wall function and 2nd order upwind is the optimum turbulence model for heat exchanger simulation.