This paper addresses the aerodynamics of a new type of Tsuji burner involving a cylindrical porous fuel injector of radius a placed at the centre of a planar air counterflow configuration with strain rate $A_{\mathrm{\infty }}$, with specific attention given to flows with large values of the Reynolds number $A_{\mathrm{\infty }}{a}^2/\nu$, where ν represents the air kinematic viscosity. For cases in which the fuel-injection velocity $U_i$ is comparable to the characteristic counterflow velocity $A_{\mathrm{\infty }}a$, the boundary layer is blown off from the cylinder surface, so that the flame is embedded in the thin twin mixing layers that form about the stream surfaces separating the outer air stream from the fuel stream. Molecular transport effects are confined to these mixing layers, while the flow structure outside is nearly inviscid, with the air-side velocity being potential, while the velocity found on the fuel side is rotational, because fuel injection generates vorticity through the requirement that fuel emerges normal to the cylinder surface. The inviscid flow is computed numerically, with use made of the streamfunction-vorticity formulation for values of the ratio of injection velocity to counterflow velocity $\mathrm{\Lambda }=U_i/\left(A_{\mathrm{\infty }}a\right)$, the only relevant parameter of the flow, ranging from small injection velocities $\mathrm{\Lambda }\ll 1$ to large injection velocities $\mathrm{\Lambda }\gg 1$. Asymptotic methods are used to investigate the form of the solution for extreme values of Λ. In the limit $\mathrm{\Lambda }\ll 1$ of weak injection, the vorticity, scaling with ${\mathrm{\Lambda }}^{-1}$, is confined to a thin near-cylinder boundary layer of thickness Λ that necessarily separates from the cylinder to form a cavity of finite size on both sides of the cylinder. In the opposite limit $\mathrm{\Lambda }\gg 1$ of strong injection, the vorticity needed to maintain the fuel flow normal to the porous cylinder is found to be small, of order $1/\ln \mathrm{\Lambda }\ll 1$, so that the flow is irrotational in the first approximation. The velocity distribution along the fuel-air interface is seen to determine the evolution of the diffusion flame, including the length of the stretched jet flames that develops along the counterflow centre plane.

本文讨论了一种新型辻燃烧器的空气动力学，该燃烧器包括一个半径为 a 的圆柱形多孔燃料喷射器，该喷射器位于具有应变率的平面空气逆流配置的中心${\mathrm{一个}}_{\mathrm{\infty }}$, 特别注意雷诺数较大的流量${\mathrm{一个}}_{\mathrm{\infty }}{\mathrm{一个}}^2/\nu$, 其中ν表示空气运动粘度。对于燃油喷射速度${ü}_{\mathrm{一世}}$与特征逆流速度相当${\mathrm{一个}}_{\mathrm{\infty }}\mathrm{一个}$，边界层从气缸表面吹掉，因此火焰嵌入薄的双混合层中，这些混合层形成在将外部空气流与燃料流分开的流表面周围。分子输运效应仅限于这些混合层，而外面的流动结构几乎是无粘性的，空气侧的速度是潜在的，而燃料侧的速度是旋转的，因为燃料喷射通过燃料出现的要求产生涡流垂直于圆柱体表面。非粘性流动是数值计算的，使用流函数-涡度公式计算注入速度与逆流速度之比的值$\mathrm{\Lambda }={ü}_{\mathrm{一世}}/\left({\mathrm{一个}}_{\mathrm{\infty }}\mathrm{一个}\right)$，流动的唯一相关参数，范围从小注入速度$\mathrm{\Lambda }\ll 1$大喷射速度$\mathrm{\Lambda }\gg 1$. 渐近方法用于研究 Λ 极值的解的形式。在极限$\mathrm{\Lambda }\ll 1$弱注入、涡度、缩放与${\mathrm{\Lambda }}^{-1}$, 被限制在厚度为 Λ 的薄的近圆柱边界层中，该边界层必然与圆柱体分离，以在圆柱体的两侧形成有限尺寸的空腔。在相反的极限$\mathrm{\Lambda }\gg 1$在强喷射的情况下，维持燃料流正常流向多孔气缸所需的涡量很小，很正常$1/\ln \mathrm{\Lambda }\ll 1$, 使得流动在第一近似中是无旋的。沿燃料-空气界面的速度分布可以确定扩散火焰的演变，包括沿逆流中心平面发展的拉伸射流火焰的长度。