Numerical Simulation And Experimental Research On Heat Transfer And Flow Performance In Shell Side Of Helical Baffled Heat Exchanger

China is the world’s second energy production and consumption country. The total reserves of energy is high, but the conventional energy per capita is far below the world average. With the rapid development of our country’s economy, at present the energy demand faces severe challenges. And heat exchanger is widely applied in various sectors, such as light industry, power generation and petroleum chemical. The improvement of heat exchanger structure and enhancement of the comprehensive heat transfer performance of heat exchanger can effectively increase the energy utilization efficiency, and reducing energy consumption and pollutant emissions. Helical baffled heat exchanger is invented as novel energy efficiency heat transfer equipment.In this paper, methods of numerical simulation and experiment research are applied to study the influence of different types of helical baffles on the shell-side fluid flow, heat transfer and resistance performance of heat exchangers. Then the best way of helical baffle optimization is obtained. The main work is as follows:1. The simplified model of helical baffled heat exchanger is established by the Pro/E software. ICEM software with mesh adaptive technology is used to partition unstructured grid of the model, and grid independence test is made to determine reasonable grid number and grid quality. Then the grid is imported into ANSYS CFX Pre-treatment, where the turbulent model is set as RNG k-s model, and boundary conditions and solver parameters are given. Finally numerical calculation is carried by the ANSYS CFX software and analysis is made on the basis of the results.2. Model of heat exchanger with short-circuit prevention helical baffles is established in which the square edges of the fan-shaped baffle plate widened certain width. Comparative study is made between short-circuit prevention helical baffled heat exchanger and conventional helical baffled heat exchanger with10°,20°and30°helical angle. The simulation results of shell-side fluid flow, heat transfer and resistance performance validate whether the short-circuit prevention helical baffles can reduce triangle leakage flow and enhance shell-side comprehensive heat transfer performance or not. The working condition of short-circuit prevention helical baffles are obtained.3. In order to study the influence of shape and quantity of helical baffle on the shell-side heat transfer performance of heat exchanger, the models of1/3,1/4and1/6helical baffled heat exchanger with10°,25°and40°helical angle. Numerical simulation of the models with different shape and quantity of helical baffle are carried out, and the distribution regularities of shell-side fluid flow, heat transfer and resistance performance are obtained. The analysis of the cause of distribution regularities is made and the best plate style is found out.4. The experimental platform of helical baffled heat exchanger made was set up. The shell material of the heat exchanger is transparent organic. The shell-side axial velocity distribution is measured by ultrasonic doppler velocimeter. Analysis and discussion are made on the experimental data and the cause of the axial velocity distribution regulation is obtained.