摘要
对超临界RP-3航空煤油在内径为10mm、长度为8 000mm的水平圆管内的流动与传热特性进行了数值模拟研究,重点考察了超临界航空煤油在拟临界区热物性的奇异变化对水平管内传热的影响.通过与实验数据的对比,验证了计算模型的可靠性;根据近壁区流体状态将整个换热过程分成4个阶段,并利用截面中垂线上的密度分布和二次流速度定性分析了二次流沿管轴向的变化规律,以解释壁温异常分布的机理;引入截面相对横向动能对二次流的强度进行描述,讨论了质量流速及热流密度对二次流和壁温分布的影响规律;最后,分析了浮升力影响判别准则在水平管超临界航空煤油对流换热中的适用性.计算结果表明,二次流的演变规律能合理地解释水平管内超临界RP-3航空煤油的非均匀传热机理.
Numerical simulations on flow and heat transfer characteristics of RP-3 aviation kerosene in a horizontal tube at supercritical pressure were carried out. The inner diameter of the tube is 10 ram,and the length is 8 000 mm. Influence of violent variation of thermo-physical properties in the pseudo-critical region on heat transfer in the horizontal tube was investigated. Numerical method was validated by comparing numerical results with experimental data. The entire heat transfer process was divided into four stages according to the fluid states of near-wall region. Density distribution along perpendicular bisector at different tube cross-sections and secondary flow velocities were used to analyze the evolution characteristics of the secondary flow, so the abnormal mechanism of wall temperature distribution was well explained. The parameter of cross-section relative transverse kinetic energy is introduced to qualitatively describe the intensity of the secondary flow. Effects of mass velocity and heat flux on the secondary flow and wall temperature distributions are discussed. Finally, the applicability of several criteria, used for the buoyancy effect on the convective heat transfer of supercritical aviation kerosene in the horizontal tube is analyzed. The computational results show that the heterogeneous heat transfer mechanism of RP-3 aviation kerosene at supercritical pressure in the horizontal tube can be well explained by the variation characteristics of the secondary flow.
出处
《大连理工大学学报》
EI
CAS
CSCD
北大核心
2013年第6期816-823,共8页
Journal of Dalian University of Technology
关键词
浮升力
超临界压力
航空煤油
传热
二次流
buoyancy
supercritical pressure
aviation kerosene
heat transfer
secondary flow
