Study On Heat Transfer Characteristics Of Carbon-Plastic Shell And Tube Heat Exchanger

Heat exchanger is one of the important equipment in the industrial field,and shell and tube heat exchanger is the most widely used type of heat exchanger.The existing shell and tube heat exchangers are mainly metal heat exchangers and plastic heat exchangers.Metal heat exchanger heat transfer performance is good,but there are weak corrosion resistance,easy to scale and other shortcomings;plastic heat exchanger corrosion resistance and easy to scale,but its heat transfer performance is poor.In view of the shortcomings of the above two materials,a new carbon plastic combined with aluminum shell and tube heat exchanger(abbreviated as: carbon-plastic shell and tube heat exchanger)is studied in this paper,whose heat exchanger tube is mainly composed of 2 mm thick new carbon plastic and 1 mm thick aluminum alloy.The heat transfer characteristics of the carbon-plastic heat exchanger are investigated by a combination of experimental studies and numerical simulations.The main studies are as follows:(1)The design calculation of the carbon plastic shell and tube heat exchanger,the design of the completed carbon plastic shell and tube heat exchanger size for the heat exchanger tube length of 1.5m,the number of heat exchanger tubes for 7,the shell inner diameter of 140 mm,and the design of the carbon plastic shell and tube heat exchanger for the physical processing.(2)Set up an experimental bench to experimentally study the heat transfer characteristics of the carbon plastic shell and tube heat exchanger,through the analysis of the experimental results found that the heat transfer coefficient of the carbon plastic shell and tube heat exchanger increases with the increase in hot water inlet temperature or cold water flow,while increasing the hot water inlet temperature and cold water flow will significantly increase the heat transfer coefficient of the heat exchanger,44.6% in the experimental conditions,the shell process fluid pressure drop with the shell process cold water inlet flow The shell process fluid pressure drop increases with the increase of the shell process cold water inlet flow rate,and the shell process Euler number decreases with the increase of the shell process cold water inlet flow rate.(3)ANSYS software was used to establish a carbon plastic shell and tube heat exchanger model and set the corresponding boundary conditions to simulate the conditions conducted during the experiments,and the experimental values were compared with the simulated values and found that the error of both remained below 5%,which proved the correctness of the model;and this model was used to simulate the common plastic heat exchanger,and the carbon plastic shell and tube heat exchanger was compared with the plastic heat exchanger under the same conditions.The heat transfer coefficients obtained were compared,and it was found that the heat transfer coefficients of the carbon plastic shell and tube heat exchanger were greater than those of the plastic heat exchanger under the working conditions.(4)Simulation of structural optimization of carbon plastic shell-and-tube heat exchanger is carried out on the basis of the correct model,and the effects of folding plate spacing and notch height on the temperature distribution,heat transfer coefficient,shellstage flow rate and shell-stage resistance characteristics of carbon plastic heat exchanger are mainly analyzed.The heat transfer coefficient of the carbon plastic shell and tube heat exchanger increases with the decrease of folding plate spacing and the more uniform heat exchanger temperature distribution and shell process flow rate distribution,the greater the shell process pressure drop,Euler number Eu and heat transfer coefficient per unit pressure drop h/?P;with the decrease of folding plate notch height,the greater the heat transfer coefficient and the more uniform heat exchanger temperature distribution and shell process flow rate distribution,the greater the shell process pressure drop,Euler number Eu and heat transfer coefficient per unit pressure drop h/?P.The larger the heat transfer coefficient h/?P;as the center distance of the heat exchanger tube increases,the heat transfer coefficient and the heat transfer coefficient h/?P per unit pressure drop decreases,and the shell process pressure drop and Euler number Eu increases.This paper proposes a new material of shell and tube heat exchanger--carbon plastic shell and tube heat exchanger,and studies the heat transfer characteristics of carbon plastic shell and tube heat exchanger,which provides theoretical support and technical guidance for the practical application of carbon plastic heat exchanger in the future.