Study On Heat Transfer And Flow Characteristics Of Miniature Plate In Plate Heat Exangers For CO₂ Capture

Plate heat exchangers are widely used in various industrial fields because of its advantages of small area,high heat transfer coefficient,long service life and easy installation and cleaning.In recent years,various types and structures of plate heat exchangers have been continuously developed,among which the micro-corrugated plate has the advantages of light weight,good heat transfer effect and great heat dissipation performance,that is more efficient and beneficial to be applied to all-welded plate heat exchangers in CO₂ capture system.In this paper,a fully welded plate type heat exchanger with micro corrugated plate is designed for the requirement of new adsorbent for heat exchange equipment of CO₂capture system.Based on the heat transfer characteristics and flow performance of micro corrugated plates in all-welded plate heat exchanger,a suitable turbulence model of corrugated plates and a common thermodynamic calculation method were selected by combining with CFD software.The heat transfer and flow performance of corrugated plates with 30°～80°of ripple inclination,4.2-5mm of ripple spacing and0.2～0.8mm of ripple depth at different speeds were numerically simulated,and the change curves of heat transfer and flow velocity field,temperature field and pressure field of micro corrugated plates were obtained.The influence of pressure drop,Nu,j,f and j/f on the heat transfer and flow of micro corrugated plates was analyzed based on the results of numerical simulation.And through the calculation and analysis of plate parameters and Nu,a heat transfer criterion equation of micro corrugated plate with three parameters was established.The results provide a theoretical basis for the design,development and application of all welded plate heat exchangers with micro corrugated plates.A water-to-water heat transfer and flow performance test platform for a all-welded micro corrugated plate heat exchanger was established,and the optimized micro corrugated plate was experimentally studied to verify the accuracy and reliability of the numerical simulation.According to the experimental results,the heat transfer criterion equation and the friction factor relationship are further fitted.Finally,numerical simulations of the heat transfer and flow characteristics of working fluids with different viscosities were performed on micro corrugated plate with a corrugation inclination angle of 45°,a corrugation pitch of 4.2 mm,and a corrugation height of 0.5mm.The effect of pressure drop,Nu,j,f and j/f on the heat transfer and flow of the micro corrugated plate provides a solid basis for optimizing the micro corrugated plates.