热压通风房间地面对流换热过程分析

Analysis of convective heat transfer on the floor during buoyancy-driven ventilation

全尺度实验测试了单侧热压通风房间围护结构内表面和地面热质的温度变化,分析了室内初始温度、地面初始温度和通风口尺寸对地面对流换热的影响.结果表明:通风过程中室内温度逐渐降低,温度垂直分布趋于均匀;进风气流流经的测杆处地面的局部换热量和局部对流换热系数分别大于地面平均换热量和平均对流换热系数;对于室内初始温度较高的情形,地面局部对流换热系数较大,平均对流换热系数较小;对于地面初始温度较高的情形,地面局部对流换热系数较小,平均对流换热系数较大;上大下小的通风口组合对应的地面局部对流换热系数较小,平均对流换热系数较大;若室外温度为12℃左右时,室内初始温度为13~35℃,地面初始温度为33~41℃,则地面平均对流换热系数为2~8 W·m^-2·K^-1,局部对流换热系数不超过18 W·m^-2·K^-1.

Temperatures of the inner surfaces of building envelope and the thermal mass of floor in a full-scale test room during buoyancy-driven single-sided ventilation are measured.The effects of initial indoor temperature,initial ground temperature and the vent size on the convective heat transfer on the floor are analyzed.The results show that indoor temperature decreases gradually and vertical temperature profile tends to be uniform during ventilation.The local convective heat flux and local convective heat transfer coefficient(h c)on the floor with measuring pole are greater than the mean heat flux and mean convective heat transfer coefficient(c)on the whole floor,respectively.For the case of high initial indoor temperature,h c is relatively great and is relatively small.For the case of high initial ground temperature,however,h c is relatively small and c is relatively great.For the room with big upper vent and small lower vent,h c is relatively small and c is relatively great.In general,c is between 2 and 8 W·m^-2·K^-1,and h c is less than 18 W·m^-2·K^-1 if the outdoor temperature is around 12℃,initial indoor temperature is between 13 and 35℃,initial ground temperature is between 33 and 41℃.