Experimental Study On The Convective Heat Transfer Of Supercritical Pressure N-Decane In Rotating Channel

As the temperature of the turbine engine inlet gas is getting higher and higher,the cooling problem for the turbine blades is becoming more and more severe.At present,the cooling means for the turbine blade s mainly adopts a part of air from the compressor,and cool down the cooling channels inside the blades.As the operating parameters of the engine increase,a higher cooling capacity is required.It has been proposed to use a hydrocarbon fuel carried by an aircraft to directly cool the blades or to c ool the air drawn from the compressor with hydrocarbon fuel,and then to cool the turbine blades with air.In the course of flight,the aircraft is often subjected to inertial force.At this time,the convective heat transfer law of hydrocarbon fuel in the heat exchanger needs to be studied.Based on the above research background,this paper conducts an experimental study on the supercritical pressure n-decane convective heat transfer in a rotating channel.The main conclusions obtained are as follows:For the centrifugal section:under the rotating condition,due to the Coriolis force,the temperature of the leading wall of the centrifugal section is higher than that of the trailing wall,and the heat transfer capability of the trailing wall is stronger than that of the leading wall.As the rotational speed increases,the length of the inlet section decreases and the heat exchange capacity increases.Under the rotating condition,as the heat flow density increases,the buoyancy is enhanced and the heat transfer is enhanced.When mass flow changes,the coupling of Reynolds number and lift force should be considered.As the mass flow rate increases,theBo^*decreases and the heat transfer capacity may decrease.On the whole,when1?10^-7?B o^*?7?10^-7,with the Bo^*increase,the heat transfer deteriorates and the deterioration gradually increases;when7?10^-7?B o^*?1?10^-5,the heat transfer deteriorates,but the deterioration gradually recovers;WhenBo^*?1?10^-5,the heat transfer capacity increases and gradually increases.When the supercritical pressure n-decane is exchanged in the rotating channel,the empirical correlation of the convective heat transfer due to the buoyancy and the number of revolutions is obtained.With the increase of the rotation number,the difference in heat transfer capacity between the leading and the trailing faces increases,and the critical rotation number is 0.06.At this time,the front edge surface is separated by flow,and the heat transfer is enhanced.The correlation of the difference in heat transfer capacity between the leading and trailing walls caused by the rotation number is fitted.For the centripetal section:under the rot ating condition,due to the Coriolis force,the temperature of the trailing wall of the centripetal section is higher than that of the leading wall,and the heat exchange capacity of the leading wall is stronger than that of the trailing wall.As the rotational speed increases,the length of the inlet section decreases and the heat exchange capacity increases.Under the rotating condition,the heat transfer capacity increases with the increase of heat flux density as a whole;when the mass flo w rate changes,the effects of Reynolds number,rotation number and buoyancy under different mass flow rates should be considered.On the whole,heat transfer deteriorates when1?10^-7?B o^*?1?10^-5,but with the Bo^*increases,the deterioration gradually recovers;WhenBo^*?1?10^-5,the heat transfer capacity increases and gradually increases.WhenBo^*?5?10^-5,the heat transfer capacity of the centrifugal section is stronger than that of the centrip etal section.When the supercritical pressure n-decane is exchanged in the rotating channel?central segment?,the empirical correlation of the convective heat transfer due to the buoyancy and the number of rotations is fitted.With the increase of the rot ation number,the heat transfer capacity of the front and rear edges changes,and the difference between the heat transfer capacity of the front and the rear increases first and then decreases.Finally,the heat transfer capacity of the trailing wall is stronger than that of the leading wall,which is different from the influence of the centrifugal section.The critical rotation number at this time is about 0.06.The difference correlation of heat transfer capacity caused by the rotation number is fitted.