空气源热泵换热器沙尘冲蚀磨损模拟研究

Numerical simulation on sand erosion wear of heat exchanger of air source heat pump

针对沙尘对空气源热泵平直管翅式换热器表面冲蚀磨损问题,以平直管翅式换热器为研究对象,建立换热器单一进气单元模型,运用数值模拟方法,采用SST k-ω湍流模型、拉格朗日随机轨道模型、DPM模型,研究气流速度、颗粒物粒径和浓度对换热器表面磨损规律。结果表明:随着气流速度增大,换热器表面平均磨损率呈正相关递增;随着颗粒物粒径的增大,换热器表面平均磨损呈先增大后减小最后趋于平缓的趋势,在10~30μm的粒径区间内换热管的磨损率出现峰值;随着颗粒物浓度增大,换热器表面磨损率呈线性递增;在上述3个影响因素中,大粒径颗粒物产生冲蚀磨损受气流速度的影响大于粒径的影响,浓度的影响程度最小;但小粒径和峰值粒径区间颗粒物引起的冲蚀磨损中,粒径对冲蚀的影响大于风速的影响。

For the problem of erosion-wear on the surface of the flat finned tube heat exchanger of air source heat pump caused by sand dust,with the flat tube-fin heat exchanger as the research target,a single air intake unit model of the heat exchanger was established,and the SST k-ωturbulence model,Lagrangian stochastic model,and DPM model were used to numerically study the wear laws of airflow speed,particle sizes and particle concentration on surface of the heat exchanger.The results show that with the increase of airflow speed,the average wear rate of the heat exchanger surface increases in a positive correlation;With the increase of particle size of sand dust,the average wear rate of the heat exchanger surface tends to increase first,then decrease gently,and finally tends to be flat with the peak of wear rate of the heat exchange tube appearing in the particle size range of 10~30μm.As the concentration of particulate matter increases,the wear rate on the heat exchanger surface increases linearly.Among the above three influence factors,the erosion wear of large-size particles is more affected by airflow velocity than the particle size,and the concentration has the smallest effect;but among the erosion wear caused by the particulate matters in the range from small particle size to peak particle size,the impact of particle size on erosion is greater than that of wind speed.