再生水板式换热器微生物污垢热阻的预测

Prediction of Microbial Fouling Thermal Resistance of Reclaimed Water Plate Heat Exchanger

基于细胞自动机模型,多孔介质导热模型,计算再生水在不同温度,时间条件下,流速为0.4 m/s时微生物污垢的厚度及热导率,进而计算微生物污垢热阻(称为计算值)。针对再生水放热工况,采用ANSYS FLUENT建立宽流道板式换热器模型,模拟换热器冷热流体出口温度及再生水侧压力降。将微生物污垢热阻计算值,模拟结果作为微生物污垢热阻预测模型(采用最小二乘支持向量机建立)的训练样本,验证样本,采用平均绝对百分比误差评价预测模型的准确性。预测值与计算值的平均绝对百分比误差为1.48%,说明预测模型的准确性比较高,可用于工程应用。

Based on the cellular automata model and the thermal conductivity model of porous media,the thickness and thermal conductivity of microbial fouling are calculated when the flow rate of reclaimed water is 0.4 m/s under different temperature and time conditions,then the thermal resistance of microbial fouling(called calculated value)is calculated.Aiming at the heat release conditions of the reclaimed water,a wide flow channel plate heat exchanger model is established by ANSYS FLUENT to simulate the outlet temperature of the cold and hot fluid of the heat exchanger and the pressure drop on the reclaimed water side.The calculated value and simulation result of microbial fouling thermal resistance are used as training samples and verification samples of the microbial fouling thermal resistance prediction model(built with the least squares support vector machine).The accuracy of the prediction model is evaluated by absolute mean percentage error.The absolute average percentage error between the predicted value and the calculated value is 1.48%,indicating that the accuracy of the prediction model is relatively high,and it can be used in engineering applications.