内涵工况对风扇增压级双涵匹配的影响

Influence of various core working conditions on twin-duct matching in fan booster

以某型民机大涵道比风扇增压级为研究对象,在不同转速和不同内涵工况下开展数值研究,归纳了内涵工况对外涵特性的影响规律。结果显示内涵工况移向近喘点时,外涵裕度降低,风扇近堵流量减小;掌握了获取外涵特性过程中内涵气动特性的变化规律:外涵逼喘时,内涵流量、总压比和效率始终呈现逐渐增大的趋势,而且转速越高,流量增大越明显;最终阐明了获取外涵特性时的双涵匹配机理,其本质上取决于风扇的总压比-流量特性以及内外涵流量再分配机制的共同作用。

A numerical investigation was carried out on a high bypass ratio fan booster of a civil-aircraft engine at different rotating speeds under core working conditions. The influence of core working conditions on the bypass characteristics was summarized. Results showed that the bypass surge margin and near-choke mass flow of the fan are reduced as the core condition goes to the near surge point. During the process of obtaining bypass characteristics, the change rule of core aerodynamic performance was grasped as follows: the mass flow, pressure ratio and efficiency of the core get increased as the bypass condition goes to the near surge point, and the core mass flow grows more as the rotating speed is higher. Furthermore, during the process of obtaining bypass characteristics, the twin-duct matching mechanism was clarified, which is essentially determined by the fan characteristic of total pressure ratio and mass flow, as well as the redistribution of mass flow between the core and bypass.