CAJ | 학술논문

针对主动冷却超燃冲压发动机的实际工作条件，利用电加热管设备开展了超临界压力正十烷流动和传热特性实验，目的在于获得适用于发动机传热设计的燃料对流传热关联式。管子材料为不锈钢、内径1．5 mm、外径3．0mm、长度1300mm。采用K型热电偶测量管壁沿程外壁温。实验中正十烷压力约4．0～4．3MPa，温度约335～870K，流量分别为0．93、1．24和1．86g/s。正十烷的流动经历了层流、过渡和湍流3种流态。采用最小二乘法拟合实验数据，获得了正十烷在3种流态下的传热关联式。通过外壁温计算值与实验值的对比，验证了本文给出的传热关联式的适用性。
침대주동냉각초연충압발동궤적실제공작조건，이용전가열관설비개전료초림계압력정십완류동화전열특성실험，목적재우획득괄용우발동궤전열설계적연료대류전열관련식。관자재료위불수강、내경1．5 mm、외경3．0mm、장도1300mm。채용K형열전우측량관벽연정외벽온。실험중정십완압력약4．0～4．3MPa，온도약335～870K，류량분별위0．93、1．24화1．86g/s。정십완적류동경력료층류、과도화단류3충류태。채용최소이승법의합실험수거，획득료정십완재3충류태하적전열관련식。통과외벽온계산치여실험치적대비，험증료본문급출적전열관련식적괄용성。
The flow and heat transfer of n-decane under supercritical pressure were studied ex-perimentally using an electrically heated tube according to the conditions in a regenerative cooling scramjet.The fuel was heated in a 1.5 mm inner diameter tube of 1Cr18Ni9Ti,and the total length of the tube was 1300mm.The fuel mass fluxes were 0.93g/s,1.24g/s and 1.86g/s in the three runs respectively.Seventeen type K and 0.3mm outer diameter thermocouples were spot welded directly to the outer surface of the tube to measure outer wall temperatures.The pressure of n-decane was varied from 4.0 to 4.3MPa,and the fuel temperature was varied from 335 to 870K in the experiments.The Reynolds number ranged from about 800 to 70000 and Prandtl number ranged from about 0 to 1 5 .Blank tube heating experiments were used to calibrate the tube thermal loss rate at different temperatures.At the positions within 0~0.2m and 1.2~1.3m along tube,inner wall heat flux was smaller due to additional thermal loss by the joint metal blocks near the inlet and outlet.Especially within 1 .2~1 .3m which was near the outlet,the tube temperatures were much higher than those within 0~0.2m near the inlet,so the inner wall heat flux drops steeply down.In the tests the data within 0.2~1.2m along tube were chosen for stud-y.The heat transfer correlations of n-decane in laminar,transition and turbulent flow regions were determined using the method of least squares curve fitting.The calculated outer wall tem-peratures were compared with experimental values,which confirmed the validity of the presented correlations .