Study On The Structural Design And Heat Transfer Performance Of A New Type Of Baffle Unit

As a commonly used heat exchange equipment,the shell-and-tube heat exchanger is widely used in various industrial sectors.The improvement of its heat transfer efficiency and comprehensive heat transfer performance has always been the focus of researchers.Due to the complexity of fluid flow and heat transfer in the shell side of the shell-and-tube heat exchanger,and its shell side has always had pain points such as large pressure drop and large heat transfer dead zone area,the research on shell side fluid flow and heat transfer has become The key to improve the heat transfer efficiency and comprehensive heat transfer performance of the shelland-tube heat exchanger.This article starts with the baffle parts of the shell side,with the purpose of improving the pain points of the shell-and-tube heat exchanger and improving the comprehensive heat transfer performance of the shell side,the following research work is mainly carried out:(1)Based on the hole structure of the single bow baffle,the shape of the hole was improved and the geometric models of square hole baffle,continuous hole baffle and cross hole baffle were established.(2)Established the shell side structure model of single arc baffle,square hole baffle,continuous hole baffle and cross hole baffle,and established the shell side fluid domain of different plate hole baffles based on them Model,using FLUENT to carry out numerical simulation analysis on four fluid domain models,and obtain the pressure,temperature,velocity distribution and shell side heat transfer coefficient of different plate-hole baffle heat exchangers.Furthermore,it is concluded that the comprehensive heat transfer performance and heat transfer efficiency of the shell side of the square hole baffle and the continuous hole baffle are better than the shell side of the single arc baffle;the heat transfer efficiency of the shell side of the cross hole baffle is the highest,but its comprehensive The heat transfer performance is equivalent to that of the shell side of a single arcuate baffle;the comprehensive heat transfer performance of the shell side of a square hole baffle is the best.(3)The shell side of the heat exchanger was numerically simulated by changing the height,spacing and thickness of the baffle plate with different holes.The pressure,temperature and velocity distribution and the heat transfer coefficient of the shell side of the four baffle plates were obtained under different notch height,spacing and thickness.The results show that the change of notch height and spacing has great influence on the fluid flow and heat transfer in the shell side of the baffle plate with circular hole,but little influence on the shell side of the baffle plate with special hole.The thickness of the baffle has little effect on the fluid flow and heat transfer in the shell side of the four baffles.(4)Analyze the applicability of the comprehensive heat transfer performance coefficient of the shell side.According to the JF factor evaluation index of the shell side of the heat exchanger,a new evaluation index of the shell side-the JF factor of the shell side is established,and the numerical simulation results are evaluated.When the basic parameters of the process are fixed,the number of baffles is 6,that is when the baffle spacing is 300 mm,the comprehensive performance of the shell side of the special-shaped hole baffle is the best;the comprehensive heat transfer performance coefficient and the shell side JF factor are obtained,When the height of the baffle is 0.3D,the comprehensive heat transfer performance of the shell side of the special-shaped hole baffle reaches the best;if the shell side conditions allow,the smaller the fluid velocity in the shell side,the better the heat transfer effect.