CAJ | 학술논문

通过实验研究了一种新型涡轮叶片冷却技术(Thermal driving in high centrifugal field,TDHCF)的换热特性.该技术主要利用高彻体力场下微小封闭循环通道内流体的热驱动运动来达到高效换热的目的.实验中分别采用了液态H2O和氟利昂R12为热驱动介质,分析了离心力场下热驱动运动的流动规律和换热特性,讨论了TDHCF技术的总平均换热效果KH随旋转速度和热流密度的变化规律.研究发现:离心力场下,采用不同的流体作为热驱动介质所形成的热驱动运动规律相同,温度分布也基本类似,均是随着转速和热流密度的增加,热驱动运动强度提高,平均换热系数随之变大.研究结果表明:旋转速度、热流密度以及热驱动介质的热物性均影响了TDHCF所最终能达到的换热效果,其中旋转速度的影响尤为显著;在热流密度或转速不变的情况下,以液态氟利昂R12为热驱动介质,TDHCF可以达到更高的强化换热效果.与常规的气冷技术相比,采用TDHCF可以有效地提高换热效果.
통과실험연구료일충신형와륜협편냉각기술(Thermal driving in high centrifugal field,TDHCF)적환열특성.해기술주요이용고철체력장하미소봉폐순배통도내류체적열구동운동래체도고효환열적목적.실험중분별채용료액태H2O화불리앙R12위열구동개질,분석료리심력장하열구동운동적류동규률화환열특성,토론료TDHCF기술적총평균환열효과KH수선전속도화열류밀도적변화규률.연구발현:리심력장하,채용불동적류체작위열구동개질소형성적열구동운동규률상동,온도분포야기본유사,균시수착전속화열류밀도적증가,열구동운동강도제고,평균환열계수수지변대.연구결과표명:선전속도、열류밀도이급열구동개질적열물성균영향료TDHCF소최종능체도적환열효과,기중선전속도적영향우위현저;재열류밀도혹전속불변적정황하,이액태불리앙R12위열구동개질,TDHCF가이체도경고적강화환열효과.여상규적기랭기술상비,채용TDHCF가이유효지제고환열효과.
A new cooling technique based on thermal driving in high centrifugal field (TDHCF) is developed for gas turbine rotational components, such as turbine blades. The key point of TDHCF is to enhance heat transfer by the fluid thermal driving in closed loop small channels placed in the high centrifugal field. Heat transfer characteristics of the new cooling technique are analyzed. In experiments, two different fluids (liquid water and Freon R12) are used as thermal driving media (fluid inside the loop channel). And the channel width d is 1 mm and the height h is 30 mm. The temperature is measured by thermocouples and an average heat transfer coefficient KH is defined to indicate heat transfer capacity of TDHCF. Experimental results show that KH is enhanced when heat flux and the rotating speed increase. And thermal properties of thermal driving media are also influenced by KH. Larger KH can be achieved by using Freon R12 as thermal driving medium compared with using liquid water. It can increase to 2 300 W/(m2*K) and it is much higher than that of the normal air cooling method (usually at the level of 600-1 200 W/(m2*K)). All fundamental studies of TDHCF show that there actually exists thermal driving in the closed loop small channel in the centrifugal field to improve heat transfer characteristics.