Research And Calculation Software Writing For Chevron BPHE Under Low Reynolds Number

Heat exchangers are the most commonly used energy-consuming equipment in industrial production.Reducing the volume of the heat exchanger and realizing a large amount of heat exchange at the expense of smaller flow losses can effectively improve energy efficiency and ease energy crisis.In the engineering application,a group of company D's Brazed Plate Heat Exchangers(BPHEs)working with high viscosity fluid and low Re faced the problem that the existing formula can't predict the heat exchanger correctly,which lead to the inaccurate selection of types.The formula needs to be modified.In the R&D process,due to the complexity of BPHE flow path,the existing numerical simulation methods consume a large amount of computing resources and the accuracy is difficult to ensure;the experimental method takes a long time and high costs.The establishment of a unified friction resistance prediction model can eliminate simulation and experimentation,greatly shorten the research and development cycle,and reduce research and development costs.In summary,it's of great value to study the resistance characteristics of the chevron BPHEs and establish a friction resistance coefficient prediction model suitable for a variety of plate types.This paper analyzes the resistance characteristics of chevron BPHEs under low Re flow,corrects the resistance prediction software of the company D,and establishes a prediction model for the friction resistance coefficient applicable to various plate types.By combining the means of experimental testing,theoretical analysis and neural network modeling,the resistance characteristics of seven kinds of chevron BPHEs with an equivalent diameter of about 4 mm in the range of 5<Re<50 were researched.The work done in this paper is as follows:(1)an experimental bench for measuring the pressure drop of the PHE accurately and quickly was built,and the pressure drop data of more than 500 groups was measured;(2)the resistance of the chevron BPHE at low Re flow was analyzed and seven correlations between the frictional resistance coefficient and Re were fitted;(3)general model for predicting the frictional resistance coefficient of chevron BPHEs in the flow range of 5<Re<50 was established;(4)the sensitivity of construction parameters to the frictional resistance coefficient was analyzed;(5)the pressure drop engineering calculation software for Company D was compiled.It's found that the friction coefficient of a BPHE is a single value function of Re,and the relationship between the two forms a power function;the friction coefficient of different types is similar to the variation trend of Re,but the amplitude is different.The power of Re can be approximated fixed as a constant;the effect of corrugation angle on the coefficient of frictional resistance is greater than the corrugation pitch/corrugation height,both of which are positively related to the coefficient of frictional resistance.The work in this paper can both solve the problem of company D and provide theoretical reference for the design chevron BPHE.The disadvantage is that there are few data used to train the neural network,and the obtained model has less applicability.