单层玻璃和中空玻璃传热过程及U值影响因素分析

通过对单层玻璃和中空玻璃传热过程的分析,建立了数值计算模型,给出了U值计算公式;并采用数值迭代的方法分析了玻璃厚度、中空气体层厚度、表面辐射率、综合换热系数对玻璃U值的影响规律。研究结果表明:随着玻璃厚度的增加,单层玻璃和中空玻璃的U值均逐渐降低;但降幅有限。随着中空气体层厚度的增大,中空玻璃U值先减小后增大。随着玻璃表面辐射率的增加,单层玻璃和中空玻璃的U值逐渐增大,各表面辐射率对U值影响程度不同;随着室内外环境综合换热系数的增加,单层玻璃和中空玻璃的U值均逐渐增大,但增幅越来越小。

Analysis of Heat Transfer Process and U Value Influence Factor for Single Glass and Insulating Glass

Heat transfer processes through single glass and insulating glass were analyzed and numerical calculation models of them were set up. The calculation formulas of single glass and insulating glass were given. The influence rule of glass thickness, gas gap between two glass sheets, the emissivity of the glass surface and integrated heat transfer coefficient on U value was studied by numerical iterative methods. The results show that: as the increase of glass thickness, the U value of both single glass and insulating glass gradually decreases, but the decreasing amplitude is low. W ith increasing gas gap between two glass sheets the U value gradually decreases to a critical point and then slowly goes up. With increasing emissivity of glass surface, the U value gradually increases, but the influence level of emissivity of each glass surface is different. As the increase of indoor and outdoor integrated heat transfer coefficient, the U value gradually increases, but the increasing amplitude is low.