Overtime, reduction in the amount of heat generated in engineering systems in operations have been of great concern and have continuously been under study. It is in line with the above that this research work develope...Overtime, reduction in the amount of heat generated in engineering systems in operations have been of great concern and have continuously been under study. It is in line with the above that this research work developed a mathematical model of an evaporative cooling pad using sintered Nigerian clay. A physical model of the evaporative cooling phenomenon was developed followed by the derivation of the governing equations describing the energy and mass transfer for the clay model from the laws of conservation of continuum mechanics. A set of reasonable and appropriate as-sumptions were imposed upon the physical model. Constitutive relationships were also developed for further analysis of the developed equations. The finite element model of numerical methods was used to analyse the energy transfer governing equations which resulted in the determination of the temperature of the exposed boundary surface at any given time, t2 after the commencement of the evaporative cooling processes. In this paper, it was found out that surface temperature differences could be as much as 6?C in the first cycle of evaporative cooling with the potential of further reduction. Further, an equation for the prediction of the effectiveness of an evaporative cooling system using clay modeled cooling pads was developed. The findings in this research work can be applied in the design, construction and maintenance of evaporative coolers used to dissipate waste heat when a large amount of natural water is not readily available or if for environmental and safety reasons the large water body can no longer absorb waste heat.展开更多
The present work summed up and analyzed the heat transfer experiment results ina channel bounded by parallel plates filled with spheres. The investigation indicates thatunder a certain width of the channel, the averag...The present work summed up and analyzed the heat transfer experiment results ina channel bounded by parallel plates filled with spheres. The investigation indicates thatunder a certain width of the channel, the average Nusselt number is non--linear with thesphere diameter, which implies there exists optimal filling layer number. The experimentresult concludes, filled with small spheres can gain better heat transfer enhancement effect,meanwhile the flow resistance is much less than the flow resistance when filled with tinysphere, so the method of fill small sphere can be used to augment heat transfer in commonconditions.展开更多
文摘Overtime, reduction in the amount of heat generated in engineering systems in operations have been of great concern and have continuously been under study. It is in line with the above that this research work developed a mathematical model of an evaporative cooling pad using sintered Nigerian clay. A physical model of the evaporative cooling phenomenon was developed followed by the derivation of the governing equations describing the energy and mass transfer for the clay model from the laws of conservation of continuum mechanics. A set of reasonable and appropriate as-sumptions were imposed upon the physical model. Constitutive relationships were also developed for further analysis of the developed equations. The finite element model of numerical methods was used to analyse the energy transfer governing equations which resulted in the determination of the temperature of the exposed boundary surface at any given time, t2 after the commencement of the evaporative cooling processes. In this paper, it was found out that surface temperature differences could be as much as 6?C in the first cycle of evaporative cooling with the potential of further reduction. Further, an equation for the prediction of the effectiveness of an evaporative cooling system using clay modeled cooling pads was developed. The findings in this research work can be applied in the design, construction and maintenance of evaporative coolers used to dissipate waste heat when a large amount of natural water is not readily available or if for environmental and safety reasons the large water body can no longer absorb waste heat.
文摘The present work summed up and analyzed the heat transfer experiment results ina channel bounded by parallel plates filled with spheres. The investigation indicates thatunder a certain width of the channel, the average Nusselt number is non--linear with thesphere diameter, which implies there exists optimal filling layer number. The experimentresult concludes, filled with small spheres can gain better heat transfer enhancement effect,meanwhile the flow resistance is much less than the flow resistance when filled with tinysphere, so the method of fill small sphere can be used to augment heat transfer in commonconditions.
