带前缘冲击的一体化加力支板内外耦合传热数值研究

Numerical Investigation on Internal and External Conjugate Heat Transfer Characteristics of Integrated Strut with Leading Edge Impingement

关键词:  一体化加力支板  气膜冷却  冲击冷却  对流换热  综合冷效  耦合传热

Key words:  Integrated strut  Film cooling  Impingement cooling  Convection heat transfer  Overall cooling effectiveness  Conjugate heat transfer

摘要:

以全气膜覆盖的一体化加力支板为研究对象，将冲击板布置于支板内腔中，研究气膜出流-前缘冲击复合冷却结构下一体化加力支板内外流气-固耦合传热特性。开展了不同主次流温比（2.24~2.76）、不同冲击间距（H/D=1，2.5，4）等参数对支板内外流动特性、内外壁面对流换热系数分布和支板综合冷却效率的影响规律分析。研究结果表明：冲击板结构改变了支板腔内冷气流动及各排气膜孔流量分配，随着冲击间距的增大，冲击腔内对应气膜孔冷气量依次下降2.68%，3.80%，7.14%；此外，冲击板结构增强了支板前缘内外壁面对流换热，其中对内壁面对流换热的强化更为显著，前缘冲击滞止线处对流换热系数提升幅度依次为298.3%，354.5%，271.9%；冲击板的存在提高了壁温分布均匀性，而整体平均综合冷效随冲击间距的增大而增大，分别提升1.64%，2.26%，2.62%；随着主次流温比的增大，支板的综合冷效减小，但是下降的趋势逐渐减小；在主次流流量不变的情况下，随着冲击间距的增大，主次流压比减小，相比无冲击板模型，其变化幅度依次为0.395%，0.012%，-0.650%。

Abstract:

Taking the integrated strut with full film coverage cooling as the research object， the impingement plate was arranged in the inner cavity of the integrated strut. The conjugate gas-solid coupling heat transfer characteristics of internal and external flow on integrated strut with composite cooling structure of outflow film and impingement cooling were studied. The effects of different primary and secondary flow temperature ratios （2.24~2.76） and impingement spacing on the internal and external flow characteristics and the convective heat transfer coefficient distribution and the overall cooling effectiveness of integrated strut were analyzed. The results indicate that the impingement plate changes the coolant flow in the inner cavity of integrated strut and the flow distribution of film hole. With the increase of the impingement spacing（H/D=1，2.5，4）， the coolant mass flow of the corresponding film hole in the impingement cavity decreases by 2.68%， 3.80% and 7.14%. In addition， the impingement plate enhances the convection heat transfer on the internal and external wall of the leading edge， especially the internal wall. The increase of the convection heat transfer coefficient at the impingement stagnation line of leading edge is 298.3%， 354.5% and 271.9%， respectively. The existence of impingement plate improves the uniformity of wall temperature distribution， and the average overall cooling effectiveness elevates with the raise of impingement spacing， which increases by 1.64%， 2.26% and 2.62%， respectively. With the increase of primary and secondary flow temperature ratio， the overall cooling effectiveness of the strut decreases， but the downward trend gradually declines. In the case of constant mainstream and coolant flow， with the increase of impingement spacing， the mainstream and coolant pressure ratio decreases. Compared with the non-impingement plate model， the variation ranges are 0.395%， 0.012%， -0.650%， respectively.