Development And Process Research Of Orthogonal Curtain Baffle Heat Exchanger

Controlling energy is the key to increasing national strength,and green and efficient development will become the future direction of my country’s energy system construction.As an important energy exchange device,the shell-and-tube heat exchanger is widely used in the fields of chemical industry,HVAC,energy electronics,etc.Its numerical simulation method and structural design and development have always attracted attention.This paper proposes a "period model" simulation method to study the double torsion flow and oblique flow conditions in the shell side of the heat exchanger,and develops the orthogonal curtain baffle heat exchanger.The main research work and conclusions are as follows:(1)Establish the whole and periodic calculation model of the torsion flow heat exchanger,analyze the fluid flow in the shell side,and compare the relationship between the average heat transfer coefficient and the average velocity of the shell side of the two.The results show that the Reynolds number is in the range of 5000～15000,and the fluid in the shell side of the torsion flow heat exchanger presents a periodic flow pattern.The average heat transfer coefficient and average velocity error calculated by the periodic model simulation are 0.69%～5.83% and 8.54%～11.07%,respectively.Verified the applicability of the periodic model,that is,the relevant parameters of flow and heat transfer in periodic geometric sections can replace the numerical simulation results of the overall model.The cycle model is used to numerically study the heat transfer coefficient,flow resistance and comprehensive performance of the shell side of the double torsion flow heat exchanger.The results show that the double torsional flow heat exchanger induces the fluid to produce spiral flow due to the two-way orthogonal arrangement of the baffles,and the speed and pressure gradient synergy angle is larger than that of the torsion flow heat exchanger,and the fluid flow resistance is relatively small.The pressure drop of the heat exchanger is reduced by 63.3%～71.0%.The principle of field synergy is used to reveal the internal mechanism of the double torsion flow heat exchanger to reduce resistance;the fluid with higher shell side flow velocity is distributed near the cylinder,which is not conducive to scouring the tube wall and twisting The shell side fluid velocity and temperature gradient of the flow heat exchanger have a good synergy,which is beneficial to strengthen the convection heat transfer.The shell side heat transfer coefficient is relatively large,so the heat transfer coefficient of the double torsion flow heat exchanger is lower than that of the trapezoidal baffle heat exchanger 24.4%～27.9%.(2)Set up an experimental platform to conduct a cold model test on a double torsion flow heat exchanger,and use a laser Doppler velocimeter(LDV)to measure the speed on the designated verification line.Compared with the numerical simulation calculation speed,the error is ±19.6%.Analyzing the error results and the causes can prove the accuracy of the simulation methods and results to a certain extent.(3)A new type of orthogonal curtain baffle heat exchanger was developed,and the shell side performance was analyzed.The results showed that the orthogonal curtain baffle heat exchanger was arranged orthogonally to change the direction of the fluid.The overall flow is in the form of spiral flow in the outer ring of the shell side and transverse flow in the inner ring.The fluid is evenly distributed.Compared with the conventional curtain baffle heat exchanger,the heat transfer coefficient is reduced by 26.5%～32.9%,and the pressure drop is reduced by 49.2%～51.5%.,The comprehensive performance is increased by 4.1%～4.9%,which can change the traditional view of sacrificing the pressure drop to improve the heat transfer capacity,and improve the overall comprehensive performance of the shell-and-tube heat exchanger by effectively reducing the pressure drop.Orthogonal experiments are designed to perform variance analysis on different combinations of baffle geometry.The results show that the number of baffles has an extremely significant impact on the pressure drop of the shell side and the Nusselt number.The width of the baffles has a significant impact on the overall performance,which provides a reference for optimizing the performance of the heat exchanger.Compile the Matlab software program to fit the Reynolds number in the range of 4000 to 12000,the Nusselt number and the resistance factor correlation equation,and use the residual to verify.It provides a reference for the application of the new heat exchanger.(4)Discuss the processing and assembly process of the key components of the orthogonal curtain baffle heat exchanger,clarify that the baffle manufacturing method is the "ladder projection",and the tube bundle assembly process uses the assembly frame to work,which provides a reference for practical engineering applications.