Research On Numerical Calculations For Heat Transfer Enhancement Of Partial Condenser

Condenser is the core component of the condenser equipment.Condenser is an important part of the power plant thermal cycle.The performance of the condenser directly affects the safety,stability and economic operation of entire power station.Condenser vacuum is an important indicator of the performance characteristics of the condenser.If the condenser vacuum is too low,the economic operation of whole unit would be affected,and the amount of coal for power consumption would increase.The role of the condenser air cooling zone is to condense the steam that flowed through the main condensation area but haven't been condensed,and to cool down the non-condensable gas in the steam to decrease the load of the pumping equipment.Most of the steam would be condensed when it flows through the main condensation zone,then the mass content of the steam decreases with the condensation of the steam,and the mass content of the non-condensing gas increases.The result is that the thermal resistance of air cooling area is higher than main condensation area,and the heat transfer coefficient of air cooling area is lower than main condensation area.Compared with the main condensation zone,air cooling area becomes a weak heat transfer zone of the condenser.Current researches on improving the heat transfer of condenser are most focused on changing the internal structure of condenser or using new kind of heat transfer tubes.This research area now lacks of researches on improving the heat transfer of air cooling area,which is a weak heat transfer zone of the condenser.This paper is aimed at the condenser air cooling zone.This paper established a physical model of condenser air cooling zone,and a mathematical model based on the physical model.Through numerical calculation,this paper studied the regular pattern of strengthening partial tube bundle's heat transfer of condenser air cooling zone.Partial tube bundle of condenser air cooling zone was strengthened by using heat pump evaporator tubes at low temperature,instead of cooling water tubes at room temperature.Heat pump evaporator tubes at low temperature became a fast cooling zone in air cooling zone.The specific work carried out in this paper is as follows:1.This article carried out the heat transfer analysis of the condenser,especially of the air cooling zone.2.This article established a physical model of condenser air cooling zone based on the experiment of using heat pump evaporator to strengthen the heat transfer of condenser air cooling zone,and established a mathematical model based on this physical model.3.This article used the mathematical model of condenser air cooling zone strengthened by heat pump evaporator to study the influence of heat transfer of air cooling zone by different "fast cooling area" settled in air cooling zone.The numerical result shows that,no matter the "fast cooling area" was settled in the first place,the second place or the last place,no matter the "fast cooling area" was consisted of one group,two groups or three groups of heat transfer tubes,the heat transfer coefficient of air cooling zone has always been raised,and the condenser pressure has always been reduced.4.This article used the mathematical model of condenser air cooling zone strengthened by heat pump evaporator to study the influence of heat transfer of air cooling zone by different "fast cooling area" settled in air cooling zone.It turned out that,a "fast cooling area" contained three neighboring groups of heat transfer tubes would make heat transfer coefficient of air cooling zone higher and condenser pressure lower than a "fast cooling area" contained two neighboring groups of heat transfer tubes.And a "fast cooling area" settled near the steam outlet in air cooling zone would be better than a "fast cooling area" settled near the steam inlet in air cooling zone.5.This article used the mathematical model of condenser air cooling zone strengthened by heat pump evaporator to study the influence of heat transfer of air cooling zone by different "fast cooling area" settled in air cooling zone.It turned out that,a "fast cooling area" contained two dispersed groups of heat transfer tubes would make heat transfer coefficient of air cooling zone higher and condenser pressure lower than a "fast cooling area" contained three dispersed groups of heat transfer tubes.And a "fast cooling area" settled near the steam outlet in air cooling zone would be better than a "fast cooling area"settled near the steam inlet in air cooling zone.In summary,to set up a "fast cooling area" in condenser air cooling zone is practical and functional in engineering applications.A "fast cooling area" could raise the heat transfer coefficient and improve power plant economy.Research by this article can be used to guide real power plant condenser to transform.