| The intubated heat exchanger is a flow path established between the inside of the heat exchange tube and the cover,and the heat is transferred to the cold fluid by the hot fluid.At present,the research on improving the heat transfer performance of the intubated heat exchanger is mainly based on the way of inserting the internal parts in the heat exchange tube and the method of cleaning the heat exchanger tube.Though the two strengthen the heat transfer performance of the heat exchanger,the experiment cost is high and the operation is difficult.Therefore,this paper proposes to apply tube sorting optimization to the intubation heat exchanger,which is mainly divided into three parts: tube sorting optimization,numerical simulation analysis,and experimental verification.First,the tube sorting method of the intubation heat exchanger is optimized,and is divided into a fork row arrangement and a side row arrangement.The optimization results show that the heat transfer performance of the fork-displacement heat exchanger is stronger than that of the arrangement heat exchanger.Under the same boundary conditions,the maximum air temperature in the cross-displacement heat exchanger is higher than 33 K in the row;the analysis of the two tube rows by PEC comprehensive performance assessment shows that the comprehensive performance assessment of the fork row is higher than that under the same Reynolds number.20%-30% of the row;under the same conditions,the fork row arrangement heat exchanger is not only efficient,but also reduces the heat exchanger area,which reduces the cost and saves energy.Secondly,the three-dimensional design of the process requirements of the heat exchanger related structure was carried out,and the intubation heat exchanger model was established by Gambit software,and boundary conditions were set.Influent was introduced into the Fluent,and the relevant parameters of the intubation heat exchanger were set and the values were calculated.simulation.The results of the simulation show that the air outlet speed is about 1.8 and the air outlet temperature is about 389 K,which meets the process requirements.The numerical simulation results of the intubation heat exchanger show that with the gradual increase of the speed,the air temperature after heat exchange is gradually reduced;increasing the diameter of the heat exchange tube can make the heat exchange effect better.Finally,the experimental platform is built,the experimental data is measured,the experimental data is processed,and the uncertainty of the experimental data is verified by calculating the uncertainty of the data.The uncertainty of the calculated heat transfer amount Qs in the main heat exchange zone is 5.23%.Within the confine,the uncertainty of the surface heat transfer coefficient hs is within 6.42%,the uncertainty of the average Nusselt number Nu is less than 4.81%,and the uncertainty of the resistance coefficient fs is within 6.64%.The results of each parameter satisfy the error requirement..Comparing the experimental values of the Nusselt number with the theoretical prediction values,it is found that the deviation is about 6.12%,and the accuracy of the experimental data is verified.The advantage of this paper is to optimize the heat exchanger tube that space in the intubation and improve the heat transfer performance of the intubation heat exchanger.The CFD software is used to simulate the heat,flow and solid coupling of the heat exchanger.,get the speed and temperature results of air inlet and outlet,compare experimental analysis,and achieve energy saving effect. |
