液晶瞬态技术测量带侧向流扰流柱通道端壁换热

Measurements of endwall heat transfer in pin-fin array duct with lateral-flow by using transient liquid crystal technique

关键词:  液晶  扰流柱通道+  侧流比+  传热

Key words:  Liquid crystal  Pin fin array+  Lateral-flow ratio  Heat transfer

摘要:

采用热色液晶瞬态测量技术测量带侧向流扰流柱通道端壁全表面换热系数的分布,研究了侧流比及雷诺数对换热的影响,其中,侧流比为0.25~1.0,雷诺数为3×104~9×104。结果表明:(1)侧流比对扰流柱通道的流动形态及端壁换热有重要影响;(2)存在一个临界侧流比,在临界侧流比以下,流动形态沿主流方向呈错排流状态;在临界侧流比以上,流动形态沿侧流方向呈错排流状态;在临界侧流比附近,流动为顺排流动状态,方向在主流和侧流方向之间;(3)侧流比较小或较大时,扰流柱通道端壁换热较强;在临界侧流比附近,换热相对较弱。

Abstract:

Measurements of endwall heat transfer in pin fin array duct with lateral-flow are made by using transient liquid crystal technique.The effects of Reynolds number and lateral-flow ratio on the heat transfer are investigated.The lateral-flow Reynolds numbers range from 3×104 to 9×104 and lateral-flow ratios range from 0.25 to 1.0.Results show that:(1) The lateral-flow ratio effects on the flow state and endwall heat transfer in pin fin array duct are important.(2) A critical lateral-flow ratio is found.The pin fin array flow is in staggered flow state in the mainstream flow direction when the lateral flow ratio is lower than this critical ratio.The pin fin array flow is in staggered flow state in the lateral-flow direction when the lateral flow ratio is higher than this critical ratio.The pin fin array flow is in aligned flow state in the flow direction between mainstream and lateral flow when the lateral flow ratio is equal to this critical ratio.(3) When the lateral flow ratio is higher or lower than the critical ratio,the average endwall heat transfer coefficients are higher.When the lateral flow ratio is close to the critical ratio,the average endwall heat transfer coefficients are lower.