大型无相变板式换热器降尺度方法和实验研究
Downscaling method and experimental study on large-scale plate heat exchangers without phase change
摘要：
针对大型无相变板式换热器在工业应用中全尺寸热工性能实验验证的难题,系统研究了基于AHRI 400与EN 1148标准的板式换热器降尺度方法,并通过水-水板式换热器实验验证了其预测全尺寸性能的可靠性。介绍了降尺度计算模型,结合板片数缩减、质量流量等比例缩放及压降修正公式,实现了全尺寸换热量与压降的间接测算。实验选取额定换热量6 000 kW的板式换热器进行降尺度(降尺度系数2.746)。结果显示:降尺度方法可有效预测全尺寸板式换热器的换热性能参数,但冷热侧压降实测值与选型值差距较大,表明现有的选型在压降性能方面留有较大裕度设计;随着降尺度系数的变化,需要对最终换热量的修正量进行同样变化,推荐降尺度系数控制在3～8范围内,以平衡实验成本与精度需求。
Abstract：
In view of the difficulty of full-scale thermal performance experimental verification of large-scale plate heat exchangers without phase change in industrial applications, a downscaling method for plate heat exchangers based on AHRI 400 and EN 1148 standards is systematically studied, and its reliability in predicting full-scale performance is verified through water-water plate heat exchanger experiments. This paper presents a downscaling calculation model, which combines the reduction of plate number, proportional scaling of mass flow rate, and pressure drop correction formula to realize indirect measurement and calculation of full-scale heat transfer and pressure drop. The experiment selects a plate heat exchanger with a rated heat transfer of 6 000 kW for downscaling (downscaling coefficient 2.746). The results show that the downscaling method can effectively predict the heat transfer performance parameters of a full-scale plate heat exchanger, but there is a large gap between the measured value of pressure drops on the cold and hot sides and the selected value, indicating that the existing selection leaves a large margin in design in terms of pressure drop performance. As the downscaling coefficient changes, the correction amount for final heat transfer needs to be varied accordingly. It is recommended that the downscaling coefficient be controlled within the range of 3 to 8 to balance experimental costs and accuracy requirements.
Keywords:plate heat exchanger; downscaling; no phase change; heat transfer; pressure drop; full scale