Forced convection of Williamson fluid flow in porous media under constant surface heat flux conditions is investigated numerically. A model of Darcy–Forchheimer–Brinkman is used and the corresponding governing equations are expressed in dimensionless forms and solved numerically using bvp4c with MATLAB package. Boundary layer velocity, shear stress, and temperature profiles, in addition to the local Nusselt number parameter over a horizontal plate, are found. The effects of the Forchheimer parameter, Nusselt number, Darcy parameter, porous inertia, and Williamson parameter on the velocity profiles, temperature profiles, coefficient of friction, and coefficient of heat transfer are investigated. The results showed that as the Darcy parameter increases, boundary layer velocity and shear stress increase, while the temperature and Nusselt number decrease. In addition, as Williamson's parameter increases, velocity within the boundary layer, shear stress, and Nusselt number decrease while the temperature profile increases. Also, with larger values of the Forchheimer parameter, the velocity of the boundary layer, shear stress, temperature, and Nusselt number increase. Furthermore, the Nusselt number and the coefficient of friction are obtained on the surface of the horizontal plate.

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This paper deals with aspects of the combined power and power (CPP) plants. Such plants consist of two major parts; the steam turbine and gas turbine plants. This study investigates the efficiency of CPP under the effect of several factors. CPP plants can achieve the highest thermal efficiency obtained with turbomachinery up to date. In this cycle, the anticipated waste thermal energy of the exhaust of gas turbine is used to generate a high pressure steam to empower the steam turbine in the steam cycle. By systematically varying the main design parameters, their influence on the CPP plant can be revealed. A comprehensive parametric study was conducted to measure the influence of the main parameter of the gas and steam cycles on the performance of CPP. The results exhibit that the overall plant thermal efficiency is significantly greater than that of either the two turbines. Due to the high thermal efficiency, a significant reduction in the greenhouse effect can be achieved. It is found that regenerative steam cycle will reduce the overall efficiency of combined cycle. On the other hand, using reheat steam cycle in the CPP plant will lead to an increase in both the thermal efficiency of the plant and the dryness factor of steam at exit of the steam turbine.

Summary The overall decrease in the size and the weight of electronic components has led to high power dissipation and the need for innovative cooling designs. The current work presents an experimental study that has been conducted to use several types of pristine and coated carbon foams as heat sink and heat exchanger in a thermoelectric cooler for cooling vest application. Various parameters were measured and calculated to investigate the performance of carbon foam. Such parameters are weight, effective thermal conductivity, mass flowrate, the outlet temperature for both heat sink, and heat exchanger in addition to their temperature difference. The results from this work were compared to a previous study conducted on aluminum fins. The results showed that the coating technique improved the thermal conductivity of the foam with low thermal conductivity more than the foam with high thermal conductivity. The performance of carbon foam was much better than aluminum in dissipating the heat, especially for the high thermal conductive carbon foam. The largest weight value of the foam was around 70% of aluminum fins, while its thermal conductivity was 300% more. The foam has the potential to improve heat transfer, thus reducing the size and the weight of equipment while simultaneously increasing its efficiency and capabilities.

This study was conducted to mathematically evaluate the impact of forced convection of viscous dissipation on a porous media filled with Williamson fluid and exposed to fixed surface heat flux. The technique of Darcy_Forchheimer_Brinkman was employed, then the non-dimensional equations were solved numerically over a flat plate by using bvp4c through the MATLAB package. Different parameters were examined including the profiles of velocity, temperature and shear_stress in addition to Nusselt Number. Furthermore, the study evaluated the effects of several essential parameters, including Forchheimer, Darcy, porous media, Williamson, and viscous dissipation, on the temperature and velocity profiles, heat transfer and friction coefficients. The numerical solution results showed that, under high Forchheimer_parameter values, all, shear_stress, Nusselt_number parameter and temperature showed an increase in their values. Also, as Williamson_parameter increased, the shear_stress and boundary layer velocity were improved, while a decrease in Nusselt_number caused an increased in values of temperature profile. Finally, the boundary layer of velocity and shear_stress showed an increase in their values when Darcy parameter increased. On the other hand, a decrease in the temperature profile and Nusselt_number were observed.