超临界CO2布雷顿循环中换热器夹点判断方法

The Judgment Method of Pinch Point of Heat Exchanger in Supercritical Carbon Dioxide Brayton Cycle

为了分析超临界CO2布雷顿循环中换热器的夹点情况,建立了换热器传热单元模型,提出了一套系统性的夹点判断方法:夹点的简化判据和分段计算分析方法。结果表明:夹点简化判据简单易行,但是实用性较为局限;分段计算是一套准确有效的夹点分析方法,能用于换热器夹点存在性、夹点位置和夹点温差的判断分析;高温回热器内一般不存在夹点,最小温差出现在换热器冷端;低温回热器和冷却器中存在夹点的可能性较大。

In order to analyze the pinch point of the heat exchanger in the supercritical carbon dioxide Brayton cycle,the heat transfer unit model is established,and a systematic pinch point judgment method is proposed,which including a simplified judgment method and a segmented calculation and analysis method.The results show that the simplified judgment method is simple and easy to use,but its practicability is limited.The segment calculation is an accurate and effective pinch point analysis method,which can be used for the judgment and analysis of pinch point existence,pinch point position,and pinch point temperature difference.There is generally no pinch point in the high temperature regenerator,and the minimum temperature difference appears at the cold end of the heat exchanger.However,there is usually a pinch point in the low temperature regenerator or the cooler.