旋转爆轰燃烧室壁面传热特性数值模拟

Numerical Investigation on Heat Transfer Characteristics of a Rotating Detonation Combustor Wall

关键词:  旋转爆轰燃烧室  热环境  热流密度  换热系数  共轭传热模拟

Key words:  Rotating detonation combustor  Heat environment  Heat flux  Heat transfer coefficient  Conjugate heat transfer simulation

摘要:

为研究旋转爆轰燃烧室的壁面传热特性，对H₂/Air旋转爆轰燃烧室进行了三维共轭传热模拟研究。建立了带壁面的燃烧室模型，采用密度基求解非稳态RANS方程，选用标准k-ε湍流模型，利用能量方程和流固界面的Interface边界条件实现壁面耦合传热，研究了旋转爆轰燃烧室非稳态流场及壁面传热特性分布。结果表明，流场中温度升高的原因包括化学反应和流体压缩两种机制。燃烧室头部附近壁面存在环形高温带，壁面温度沿轴向先上升后下降，爆轰波与斜激波交汇处附近温度最高。壁面热流密度则在头部最高，沿轴向逐渐降低。在除头部以外的其他部分，壁面换热系数沿轴向下降，进一步说明了壁面热流密度受燃烧室内部压力的影响。预混条件下，当量比越接近1.0、质量流量越大，燃烧室壁面温度越高且越集中于头部，高热流密度区域的轴向深度越短，极限热流密度越高。

Abstract:

In purpose to refine the heat transfer characteristics on the wall of rotating detonation combustor （RDC）， the 3D conjugate heat transfer simulation of H₂/Air RDC was processed and the model of combustor with shell was established.The unsteady RANS equation was solved on density basis， and the standard k-ε turbulence model was adopted， while energy equation and interface boundary condition of fluid-solid interface were used to achieve coupling heat transfer calculation. The unsteady flow field and wall heat transfer characteristics of RDC influenced by steady detonation wave were discussed. The result indicates that the temperature rise in the flow field is essentially caused by chemical reaction and fluid compression.Annular high-temperature zone persistently exists on the head of the combustor wall. Temperature rises and then decreases along theaxial direction， which peaks at the height of detonation wave. Heat flux distribution is slightly different from the temperature distribution， which peaks at the head and decrease along the axis. Except at the head， wall heat transfer coefficient decreases along the axial direction， which further indicates that heat flux is affected by the internal pressure of RDC. Under premixed conditions， when the equivalent ratio is near 1.0 or the mass flow rate is large， the wall temperature is higher and more concentrated in the head， the axial depth of the heat flux area is shorter， and the critical heat flux is higher.