Temperature distributions of internal flow and external jet fields of double serpentine convergent nozzle for turbofan

双涵道S弯喷管内/外流场的温度分布研究

Received: 10 March 2021

Abstract

In order to clarify the temperature distribution of a double-serpentine convergent nozzle wall and the exhaust plume characteristics downstream the nozzle exit based on the real exhaust mixer configuration of a turbofan engine, the temperature distribution of the internal and external jet flow fields of the double-serpentine convergent nozzle are simulated numerically. The simulation results show that the coupling effect between S-shaped circular-to-rectangular profile and the exhaust mixer has a joint influence on the "hot streak" distribution of the double-serpentine convergent nozzle wall and the exhaust plume characteristics downstream the nozzle exit. The "Hot streak" is distributed in the shape similar to several ribbons in the central areas of the upper and lower wall of the second serpentine passage and in the exit area. The maximum value of temperature on the lower wall is 867 K and increases 25.1% compared with that on the upper wall. However, the average value of temperature of the lower wall is merely 7.1% higher than that of the upper wall. The "whale tail" high-temperature core area is formed on the exit plane of the double-serpentine convergent nozzle. It leads to two wide high-temperature jet flow areas in the high-temperature core area downstream the nozzle exit. The low-temperature flow occurs along the two sides of the exhaust plume core area due to the lateral-direction motion towards vortices.

摘要

为了明晰基于真实排气混合器构型的双涵道S弯喷管的壁面温度分布及尾焰特征，数值模拟研究了双S弯收敛喷管内/外流场的温度分布特征。结果显示：排气混合器结构与S形圆转方构型共同影响着S弯喷管的壁面"热斑"分布及出口下游的尾焰特征。S弯喷管的壁面"热斑"呈带状分布，且主要存在于第二弯通道及出口区域的上、下壁面中间区域。喷管下壁面的温度峰值为867 K，相比喷管上壁面增加25.1%；但喷管下壁面的平均温度仅比上壁面高出7.1%。喷管出口截面的"鲸鱼尾形"高温核心区导致出口下游的高温核心区表现为2股较宽的高温喷流。由于流向涡的横向运动，尾焰核心区两侧出现温度较低的热流。