The Study Of The Pressure Drop Characteristics Of Plate Heat Exchanger Under Low Reynolds Number

Energy shortages and climate warming are public crisis in the 21st century.Energy-saving,emission reduction and improving the use of energy is a powerful means to solve the energy problem.The application of heat exchangers is closely linked to conservation and development of energy,and has been widely used in refrigeration,petrochemical,metallurgy,beverage,textile,paper,medicine,and electric power.It is not only a wide applied heat transfer equipment,but also occupies an important position in these fields.In the design of heat exchangers,the development of compact heat exchangers is the direction of heat exchanger optimization.If a smaller heat exchanger have more efficient heat transfer effect,it can save material production,and achieve the goal of energy saving.As an efficient and compact heat exchanger,plate heat exchangers has outstanding advantages compared to the traditional shell and tube heat exchanger.Therefore,enterprises and research workers are paying more and more attention on the plate heat exchanger.At present,the research situation of the plate heat exchanger at home and abroad is:1、research work for the traditional plate heat exchanger is more fully:2、research for special plate(micro-plate type)need to be further added;3、The study of the condition-the high viscosity working fluid operated at low Reynolds number(Re<50)is seriously inadequate.Based on the above reasons,relying on the support of company D,the flow characteristics of a variety of microplate heat exchanger for low Reynolds number with high viscosity working fluid is studied in order to supply and improve the microplate heat exchanger pressure drop database in company D,revealing microplate heat exchanger Flow law and to provide theoretical support for engineering applications.The main work and achievements of this paper are as follows:(1)Designed and built a microplate heat exchanger test bench for high viscosity working fluids.In order to verify the reliability of the experimental system,calibration work is done with the water as the working fluid,and completed the experimental system checking of repeatability and stability.(2)The six kinds of microplate heat exchangers of B3-014H、D22、33-052H、33-095H、B3-210H、and B3-095B were studied by using ISOVG320 gear oil as working fluid.Through the pressure drop test,the basic law between pressure drop and Reynolds number Re is obtained,and the difference between different plate types is studied.The results show that the pressure drop △P is increased with the Reynolds number Re increasing,and the difference of the plate type makes the variation range of the voltage drop △ P has a big difference,and the increase of pressure drop of the plate type D22、B3-052H、33-095H、B3-210H、33-095B、33-014H is from large to small.The same plate type at different temperatures,the trends of the flow resistance coefficient f with the Reynolds number Re changed are similar,among which the fluctuations are almost negligible;When used in low temperature environment,attention should be paid to the impact of high pressure drop to the heat exchanger and pressure capacity in the design process.(3)The B3-014H microplate heat exchanger was selected as the research object to simulate in order to reveal the influence of structural parameters on the internal flow field of the heat exchanger.The results show that with the increase of corrugation angle,the resistance increases gradually,reaching the maximum when the corrugation angle is about 160°,and with the corrugation angle increases and the resistance decreases.With the increase of the ripple height,the resistance decreases.The expansion of the ripple spacing can lead to the deterioration of the flow state in the heat exchanger.The ripple angle,the ripple depth and the ripple spacing affect the flow pattern of the fluid in the plate heat exchanger.With the increase of the corrugation angle,the increase of ripple depth and the decrease of spacing,the resistance within the heat exchanger channel decreases.The research results of this paper are based on the engineering practice,revealing the pressure drop characteristics of four typical micro plate heat exchangers,supplementing the D part of the product database,and also providing theoretical guidance for the development and application of the series of products to a certain degree.