为分析靠圆柱孔一侧射出的弓形截面非圆柱液流在横向气流中的脱落现象,使用CLSVOF(Couple Level Set VOF)多相流模型与大涡模拟(LES)模型相结合的方法,对非圆柱液流的脱落过程进行数值模拟。结果表明:非圆柱液流在横向气流中的脱落现象...为分析靠圆柱孔一侧射出的弓形截面非圆柱液流在横向气流中的脱落现象,使用CLSVOF(Couple Level Set VOF)多相流模型与大涡模拟(LES)模型相结合的方法,对非圆柱液流的脱落过程进行数值模拟。结果表明:非圆柱液流在横向气流中的脱落现象是由迎风面上气液密度差产生的Rayleigh-Taylor(R-T)不稳定性和液流边缘气液速度差产生的Kelvin-Helmholtz(K-H)不稳定性共同形成的表面波引起的,同时液流边缘外侧产生的连续漩涡也促进了液流的脱落;横向气流速度增加时,由于表面波增强液流的脱落量增大,横向气流方向改变时由于迎风面上的表面波现象减弱脱落量降低,说明了迎风面上形成的不稳定性表面波是引起液流脱落的主要因素。展开更多
Film cooling performance about a row of dual-fanned holes with injection angles of 30°, 60 ° and 90° were experimentally investigated at blowing ratios of 1.0 and 2.0. Dual-fanned hole is a novel shaped...Film cooling performance about a row of dual-fanned holes with injection angles of 30°, 60 ° and 90° were experimentally investigated at blowing ratios of 1.0 and 2.0. Dual-fanned hole is a novel shaped hole which has both inlet expansion and outlet expansion. A transient thermochromic liquid crystal technique was used to reveal the local values of film cooling effectiveness and heat transfer coefficient. The results show that injection angles have strong influence on the two dimensional distributions of film cooling effectiveness and heat transfer coefficient. For the small injection angle of 30 degree and small blowing ratio of 1.0, there is only a narrow spanwise region covered with film. The increase of injection angle and blowing ratio both leads to the enhanced spanwise film diffusion, but reduced local cooling ability far away from the hole. Injection angles have comprehensive influence on the averaged film cooling effectiveness for various x/d locations. As injection angles are 30 and 60 degree, two bands of high heat transfer coefficients are found in mixing region of the gas and coolant. As injection angle increases to 90 degree, the mixing leads to the enhanced heat transfer region near the film hole. The averaged heat transfer coefficient increases with the increase of injection angle.展开更多
文摘为分析靠圆柱孔一侧射出的弓形截面非圆柱液流在横向气流中的脱落现象,使用CLSVOF(Couple Level Set VOF)多相流模型与大涡模拟(LES)模型相结合的方法,对非圆柱液流的脱落过程进行数值模拟。结果表明:非圆柱液流在横向气流中的脱落现象是由迎风面上气液密度差产生的Rayleigh-Taylor(R-T)不稳定性和液流边缘气液速度差产生的Kelvin-Helmholtz(K-H)不稳定性共同形成的表面波引起的,同时液流边缘外侧产生的连续漩涡也促进了液流的脱落;横向气流速度增加时,由于表面波增强液流的脱落量增大,横向气流方向改变时由于迎风面上的表面波现象减弱脱落量降低,说明了迎风面上形成的不稳定性表面波是引起液流脱落的主要因素。
基金supported by the National Natural Science Foundation of China(Grant No.51406124)by the Natural Science Foundation of Liaoning Province of China(Grant No.201602576)
文摘Film cooling performance about a row of dual-fanned holes with injection angles of 30°, 60 ° and 90° were experimentally investigated at blowing ratios of 1.0 and 2.0. Dual-fanned hole is a novel shaped hole which has both inlet expansion and outlet expansion. A transient thermochromic liquid crystal technique was used to reveal the local values of film cooling effectiveness and heat transfer coefficient. The results show that injection angles have strong influence on the two dimensional distributions of film cooling effectiveness and heat transfer coefficient. For the small injection angle of 30 degree and small blowing ratio of 1.0, there is only a narrow spanwise region covered with film. The increase of injection angle and blowing ratio both leads to the enhanced spanwise film diffusion, but reduced local cooling ability far away from the hole. Injection angles have comprehensive influence on the averaged film cooling effectiveness for various x/d locations. As injection angles are 30 and 60 degree, two bands of high heat transfer coefficients are found in mixing region of the gas and coolant. As injection angle increases to 90 degree, the mixing leads to the enhanced heat transfer region near the film hole. The averaged heat transfer coefficient increases with the increase of injection angle.
