热压自然通风房间围护结构对热分层影响的试验研究

Experimental Investigation of Thermal Stratification Affected by Stack Ventilation Building Envelope

热压自然通风房间内,当温度场稳定时形成清晰的二区热力分层,这一现象可以通过盐水模型试验观测到。但该试验所反映的热分层现象是在墙体绝热条件下的,而实际的建筑围护结构传热是不可忽略的,空气与壁面的对流换热必然会影响室内的温度分布。本文针对含有墙体传热和太阳辐射作用的情况,建立了以空气为介质的热浮力试验台,通过对室内温度场的测试分析表明,热分层现象与墙体传热能力密切相关。若室内热量向室外传递,则会削弱分层效果,二区向多区变化;若室外热量向室内传递,则会增大分层界面的温度梯度,同时分界面的高度降低。

In a stack ventilation room, two-layer stratification can be observed and proved by a scaled-down salt-bath model experiment. But this experiment is so confined and unrealistic that it can only simulate building with adiabatic envelope. In a real building, heat transfer through envelope cant be neglected. In this paper, experiments were carried out aiming at study the thermal stratification affected by envelope heat transfer. Results showed that thermal stratification had a close relation with heat transfer through the envelopes. If heat is transferred from inside to outside, the temperature gradient at the stratification interface can be weaken, multi-layer stratification can be observed ; If heat is transferred from outside to inside, the height of the interface will descend and the temperature gradient at the stratification interface can be strengthen.