Effect of Rotating Direction on Flow and Temperature Field of Concentric Staged Combustor

旋向对中心分级燃烧室流场及温度场影响研究

School of Power and Energy, Northwestern Polytechnical University, Xi'an 710072, China

Received: 2 January 2020

Abstract

The characteristic of cold/reaction flow and temperature field were investigated by using the numerical simulation for concentric staged multi-point direct injection combustor. The interaction mechanism between the flow field and the temperature field was revealed, and the effect rules of the swirlers rotating direction on the flow and temperature field were obtained. The results indicated that the central recirculation zone with divergence angle of 17 degrees is formed under cold condition by using the co-rotating swirlers and counter-rotating swirlers, and the central recirculation zone size of co-rotating swirlers is larger than that of counter-rotating swirlers. Heat release of the flame causes the similar central recirculation zone shape is formed by using the different rotating direction swirlers, and the divergence angle increased to 45 degrees. Tangential velocity contour of different aixal sections are undergone the "circular shape", "diamond shape", "elliptical shape" and "upper-lower symmetrical" structures, which represent the formation of the central recirculation zone, initial development, full development and gradual disappearance respectively. With the decreasing of tangential velocity of the swirling air in the combustor, the axial velocity at center of near outlet and the hot spot temperature at the outlet of combustor increase. Therefore, the co-rotating swirlers combustor has a better outlet temperature distribution factor (OTDF).

摘要

采用数值模拟方法对中心分级多点直喷燃烧室冷/热态流场和温度场进行研究，揭示了流场和温度场之间的相互作用机理，获得了旋流器旋向对流场和温度场的影响规律。结果表明：冷态条件下，旋流器不同旋向时均形成了张角为17°的中心回流区，但同旋向下形成的中心回流区尺寸更大；随着燃烧释热的加入，不同旋向燃烧室形成了尺寸相同的中心回流区，而且张角增大为45°；不同轴向位置的切向速度分布云图依次形成"圆形"、"菱形"、"椭圆形"和"上下对称"结构，分别表征了中心回流区开始形成、初步发展、充分发展和逐渐消失4个过程；燃烧室内旋流空气切向速度越小，近出口中心位置的轴向速度越大，导致燃烧室出口热点温度越高，因此旋流器同旋向时具有更好的出口温度分布因数。