| Radiator is an important part of the cooling system of the generator set,its thermal performance has an important effect on the efficient and reliable operation of the generator set.It has a great significance to study the heat-transfer characteristics of the radiator and its structural optimization in practical applications.Based on the technical requirements of the cooperative industry engaged in the production of radiator,relevant research had been carried out on the thermal design and calculation of radiator,the correlation construction of flow and heat-transfer,and the optimization of structure parameter of louver,some achievements with values have been acquired(1)This paper analyzed the thermal calculation of radiator,completed the calculation of thermal design and the programme of designing louver tube belt radiator,realized the procedural and convenience of the thermal design calculation of radiator,and laid the foundation for the construction and analysis of the correlation between the flow and heat transfer of radiator.(2)In view of the importance of the correlation between the flow and heat transfer of air side in thermal design of radiator,the prediction of representative correlations between the flow and heat transfer under the same conditions were compared and calculated with the aid of the calculation program of thermal design(the wind speed of the air is 3~10m/s,the Reynolds numbers of the the characteristic length of the louver is 308~1114)The deviation of heat-transfer factor and friction factor is 2.78~60.21% and 4.79~192.95% respectively.The generality of the existing correlations between the flow and heat transfer in radiators is questionable.(3)In order to obtain the correlation between the flow and heat transfer to guide the design of radiator,the representative louver tube belt radiators produced by the enterprise were selected to do some experiments about the flow and heat transfer of radiator on the test platform.The deviation between the predicted value and the test value was compared to find that the accuracy of the prediction of Y.J.Chang heat-transfer factor correlation is the highest within the range of test conditions,and the maximum deviation from the test value is 11.12%.JunqiDong friction factor correlation has the highest prediction accuracy,with a maximum deviation of 13.24%from the test value,which basically meets the actual needs of designed radiator in enterprise.At the same time,the correlation between radiator heat dissipation and water mass flow and windspeed was obtained through test fitting.The maximum deviation between the predicted value of the correlation and the test measurement is 1.74% in the range of experimental conditions.The maximum deviation between the predicted value and the test measurement is 3.75% in the power function form of wind resistance fitting with respect to the face-to-face wind speed,which can be used for the precise design of radiators with the fixed structure in enterprise.(4)In order to provide support for the optimal design of radiator,the effects of the length and number of louver turning zone on the comprehensive performance of flow and heat transfer of radiator were simulated.The results show that the product of the length and number of the turning zone is a comprehensive factor affecting the heat-transfer factor and friction factor.At a certain face-to-face wind speed,the heat-transfer factor and friction factor decrease with the increase of the product of the length and number of the turning zone.When the product of the length and number of the turning zone is equal,the heat-transfer factor and friction factor increase with the increase of the number of the turning zone.The length of the turning zone when arranging single-row and three-row pipes is 1.5mm and 3mm respectively.The overall performance of the radiator is the best when the number of turning zones is 3.By optimizing the length and number of the turning zone,the comprehensive performance gap between the multi row pipe and the corresponding single row pipe arrangement can be effectively reduced. |
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