The Study Of Flow And Condensation Characteristics Of Non-condensable Steam On Plate Heat Exchanger

With the rapid development of my country’s economy,there is an increasing demand for condensation heat transfer.In actual industrial production,steam is often accompanied by a certain amount of non-condensable gas,which makes the condensation heat transfer process complicated.Therefore,in order to optimize the design of the relevant parameters of the heat exchanger,it is necessary to carry out research on the steam condensation phenomenon.In this paper,by using FLUENT commercial simulation software,firstly,the fluid volume function method(VOF model)is used to study the heat transfer and flow characteristics of pure steam condensation in the vertical plate domain.At the same time,based on the pure steam condensation research results,the research is conducted in the vertical plate domain.Condensate steam condensation is studied,VOF model and component transport model are used,and some UDFs are compiled to study the heat transfer and flow characteristics of non-condensable steam in the plate area.Finally,researches are carried out on the condensation heat transfer and flow characteristics in the convex-concave plate area under the two working conditions of pure steam and steam containing non-condensable gas.In the vertical plate area,analysis is carried out based on the condensate cloud diagram of steam condensation when the non-condensable gas content is 10%,20%,and 30% respectively.With the continuous increase of the non-condensable gas content,the disturbance of the liquid film increases,the integral number of the condensed liquid continues to decrease,and the thickness of the liquid film becomes thinner.When the amount of non-condensable gas increased from 0 to 30%,the amount of condensed water decreased by 33.3%.When the steam is mixed with non-condensable gas,as the amount of non-condensable gas gradually increases,the heat transfer efficiency gradually decreases.The steam condensation process in the convex-concave plate area was studied and analyzed.The control variable method was used to study and analyze the inlet flow rate,temperature difference factors,and non-condensing gas factors.It was found that the increase of the three factors all weakened the steam condensation phenomenon.However,the change of the size of the convex-concave plate has little effect on the amount of steam condensed water.When the non-condensable gas content increases from 10% to 30%,the steam condensed water volume is reduced by 40.3%.It can be seen that the non-condensable gas content has a certain influence on the condensed water volume.The steam condensation process in the convex-concave plate area was studied and analyzed,and it was found that among 13 convex-concave plates with different convex-concave platform sizes.Combining the flow resistance coefficient and the average heat transfer coefficient,the optimal plate design parameters are obtained,that is,the height of the convex-concave platform is 1.3mm,the distance between the convex-concave platform is 4mm,and the angle between the convex-concave platform is 130°,the flow resistance coefficient is the smallest,and the average heat transfer coefficient is the largest.