Sameh Nada | Benha University (original) (raw)

Papers by Sameh Nada

Energy Conversion and Management, 2015

A numerical investigation of predicting thermal characteristics of electronic equipment using car... more A numerical investigation of predicting thermal characteristics of electronic equipment using carbon foam matrix saturated with phase change material (PCM) and Nano carbon tubes as thermal management modules is presented. To study the effect of insertion of RT65 and Nano carbon tubes in carbon foam matrices of different porosities, three different modules; namely Pure CF-20, CF20 + RT65, and CF-20 + RT65/Nano carbon modules are numerically tested at different values of carbon foam porosities. Mathematical model is obtained using volume averaging technique based on single-domain energy equation and a control volume based numerical scheme. Interfacial effects influencing heat transfer process at enclosure wall, module surface and different interfacial surfaces within the composite have been addressed. Governing equations have been solved using a CFD code (Thétis, http://thetis.enscbp.fr). Mathematical model is validated by comparing its prediction with previous experimental measurements for pure CF-20 foam and CF-20 + RT65 composite modules. The model is used to predict thermal characteristics of CF-20 + RT65/Nano carbon tubes composite as a thermal management modules. Results reveal that insertion of RT65/MWCNTs in CF-20 leads to a 11.5% reduction in the module surface temperature for carbon foam porosities less than 75%. The reduction decrease to 7.8% for a porosity of 88%. Numerical results of transient and steady state temperature histories at different depths within the module are compared with previous experimental data and fair agreement is obtained.

Energy Conversion and …, 2008

In the present study, a novel indirect solar cooker with outdoor elliptical cross section, wickle... more In the present study, a novel indirect solar cooker with outdoor elliptical cross section, wickless heat pipes, flat-plate solar collector and integrated indoor PCM thermal storage and cooking unit is designed, constructed and tested under actual meteorological conditions of Giza, Egypt. Two plane reflectors are used to enhance the insolation falling on the cooker's collector, while magnesium nitrate hexahydrate (T m = 89°C, latent heat of fusion 134 kJ/kg) is used as the PCM inside the indoor cooking unit of the cooker. It is found that the average daily enhancement in the solar radiation incident on the collector surface by the south and north facing reflectors is about 24%. Different experiments have been performed on the solar cooker without load and with different loads at different loading times to study the possibility of benefit from the virtues of the elliptical cross section wickless heat pipes and PCMs in indirect solar cookers to cook food at noon and evening and to keep food warm at night and in early morning. The results indicate that the present solar cooker can be used successfully for cooking different kinds of meals at noon, afternoon and evening times, while it can be used for heating or keeping meals hot at night and early morning.

International Journal of Heat and Mass Transfer

The present article reports on experimental investigation of heat transfer and pressure drop char... more The present article reports on experimental investigation of heat transfer and pressure drop characteristics of multi tubes in tube helically coiled heat exchanger. The study aims to investigate the effects of heat exchanger geometric parameters and fluid flow parameters; namely, number of inner tubes, annulus hydraulic diameter, Reynolds numbers and input heat flux, on performance of the heat exchanger. Different coils with different numbers of inner tubes, namely, 1, 3, 4 and 5 tubes, were tested. Results showed that: (a) coil with three inner tubes has bitter heat transfer characteristics as compared with other coils, (b) coils with 3 and 4 inner tubes, respectively, have higher values of h A h (the parameter used to measure performance and compactness of compact heat exchanger) as compared to other coils, (c) for all coils and at the tested ranges of Reynolds number and heat flux, input heat flux has no effect on heat transfer coefficients, and (d) pressure drop increases with increasing

International journal of heat and mass transfer, 2007

Natural convection heat transfer in two-dimensional region formed by constant heat flux horizonta... more Natural convection heat transfer in two-dimensional region formed by constant heat flux horizontal flat tube concentrically located in cooled horizontal cylinder studied numerically. The model solved using the FLUENT CFD package. The numerical simulations covered a range of hydraulic radius ratio (5, 7.5, and 10) at orientation angles from (0 o up to 90 o ).

Heat and Mass Transfer, 2009

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International Journal of Heat and Mass Transfer, 1994

An experimental study has been made on steady state natural convection heat transfer from vertica... more An experimental study has been made on steady state natural convection heat transfer from vertical helical coiled tubes. Average heat transfer coefficients were obtained for turbulent natural convection to water. The experiments have been carried out for four coil diameter to tube ...

International Journal of Rotating Machinery, 2013

This study presents experimental and numerical investigation for three-dimensional heat transfer ... more This study presents experimental and numerical investigation for three-dimensional heat transfer characteristics in a turbine blade. An experimental setup was installed with a turbine cascade of five-blade channels. Blade heat transfer measurements were performed for the middle channel under uniform heat flux boundary conditions. Heat was supplied to the blades using twentynine electric heating strips cemented vertically on the outer surface of the blades. Distributions of heat transfer coefficient were obtained at three levels through blade height by measuring surface temperature distribution using thermocouples. To understand heat transfer characteristics, surface static pressure distributions on blade surface were also measured. Numerical investigation was performed as well to extend the investigation to locations other than those measured experimentally. Three-dimensional nonisothermal, turbulent flow was obtained by solving Reynolds averaged Navier-Stokes equations and energy equation. The shear stress transport -model was employed to represent turbulent flow. It was found through this study that secondary flow generated by flow deflection increases heat transfer coefficient on the blade suction surface. Separation lines with high heat transfer coefficients were predicted numerically with good agreement with the experimental measurements.

Energy and Buildings, 2014