风速非均匀分布对蒸发器性能的影响

Effect of Non-Uniform Air Velocity Distribution on Evaporator Performance

研究、对比了均匀和非均匀风速下蒸发器的性能,实验测量了某空调蒸发器表面的风速非均匀分布,数值模拟了该非均匀风速下蒸发器的性能,实验验证了非均匀风速下模拟结果的准确性.研究结果表明:非均匀分布时风速比均匀风速大的管路换热量较之均匀风速时的有所增加,风速比均匀风速小的管路换热量较之均匀风速时的有所减小,且换热量减小的幅度比增加的更加显著;传热系数随风速非线性增加;各支路出口状态差别越大,蒸发器换热量的衰减幅度就越大.

The performance of an evaporator with a non-uniform air velocity distribution was compared with that with a uniform air velocity distribution.The non-uniform air velocity distribution on the surface of the evaporator was measured experimentally.The evaporator simulation was conducted with the air velocity profile measured.The simulation results for the evaporator with the non-uniform air velocity distribution agree well with the experimental data.The results show that for the non-uniform air velocity profile,the capacity sum of the tubes with higher air velocity than the uniform one is greater than that for the uniform velocity.The capacity sum of the tubes with lower air velocity for the non-uniform air velocity is smaller than that for the uniform velocity,however,the decrease in the capacity sum of the tubes with lower velocity is much greater than the increase in the capacity sum of the tubes with higher air velocity.Moreover,the heat transfer coefficient has a non-linear relationship with the air velocity.In addition,the decline of the evaporator capacity increases with the difference between the circuit outlet states.