论文部分内容阅读
通过利用水平管降膜蒸发换热试验台分别对Φ19×0.75 mm的波纹管和光滑管进行实验研究。实验在变喷淋密度(0.007~0.130 kg/m·s)、变热通量(52~143 k W/m~2)、变传热温差(1.5~10.0℃)、变蒸发压力(0.020~0.065MPa)条件下进行。通过实验数据得到波纹管和光滑管传热系数与各影响因素(喷淋密度、热通量、传热温差、蒸发温度)之间的变化规律。实验结果表明:在一定范围内,降膜蒸发器的传热系数K随喷淋密度γ、热通量Q的增大、蒸发温度T的升高而增大,随传热温差Δt的增大而降低。当喷淋密度大于0.178 kg/(m·s)时,总传热系数趋于稳定,当热通量大于130 k W/m~2时,总传热系数的增速明显变缓。此外,不凝气含量对传热系数K的影响显著,在同等实验条件下波纹管的传热系数比光滑管提高近30%。
Through the use of horizontal tube falling film evaporation heat transfer test rig, respectively, on the φ19 × 0.75 mm corrugated pipe and smooth tube experimental study. The experiments were carried out under the conditions of variable spray density (0.007-0.130 kg / m · s), variable heat flux (52-143 k W / m 2), variable heat transfer temperature difference (1.5-10.0 ℃) 0.065 MPa). Through the experimental data, the change rule of the heat transfer coefficient of the corrugated pipe and the smooth pipe and various influencing factors (spray density, heat flux, heat transfer temperature difference and evaporation temperature) is obtained. The experimental results show that: in a certain range, the heat transfer coefficient K of the falling film evaporator increases with the spray density γ, the heat flux Q, the evaporation temperature T increases, with the heat transfer temperature Δt increases Lower. When the spray density is more than 0.178 kg / (m · s), the total heat transfer coefficient tends to be stable. When the heat flux is greater than 130 k W / m ~ 2, the total heat transfer coefficient slows down obviously. In addition, the effect of non-condensable gas content on the heat transfer coefficient K is significant. Under the same experimental conditions, the heat transfer coefficient of the bellows is increased by nearly 30% compared with that of the smooth tube.