Experimental study on the characteristics of axisymmetric cavity actuated supersonic flow

Abstract

The effective means of air fuel mixing and flame holding can be achieved by incorporating cavity in supersonic combustor. Understanding the complex flow field of cavity flow is essential for the design of supersonic combustor. An attempt is made to understand the characteristics of supersonic flow past axisymmetric cavity, and a series of nonreacting experiments are carried out in a blow-down type supersonic flow facility. The facility consists of a supersonic nozzle, issues a flow Mach number of 1.80 into a circular cross sectional supersonic combustor in which axisymmetric cavity is placed. Cavity of two consecutive aft wall angles is the key parameter for the study. The performance of the cavity is investigated based on the static pressure measurement, momentum flux distribution at the exit plane of the combustor, and the stagnation pressure loss of the flow. Wall static pressure distribution revealed that pressure increases with decrease in the secondary aft wall angle below 45° due to stronger recompression of shear layers. Moreover, decreasing primary aft wall angle provides a uniform mixing profile along with decrease in stagnation pressure loss across the combustor.

Non-Reacting Examination on Transverse Injection Upstream of Aft Wall Angled Cavities in an Axisymmetric Supersonic Flow

“…Thus increase in the fuel injection pressure results in increased penetration of the jet into the core stream. Unstable flow field over the cavity region for the rectangular cavity geometry, Figure 4a, results in huge variation in the momentum flux values [14]. Almost an uniform profile is observed for the (60,30), Figure 4c, cavity than the other cavities within the 60 series.…”

“…Flow over a rectangular cavity is generally influenced by the characteristics of the shear layer formed at the leading edge of the cavity which has direct influence on the flow stability and cavity drag parameters [14]. Higher static pressure values were observed at the leading edge of the cavity and is been due to the separation of the shear layer and its re-attachment at the rear wall, which results in the formation of a flapping motion and an unstable flow in the cavity region Figure 3(a) shows analogous profile for the flow over rectangular cavity (90,90) during 'No-injection' case.…”

“…It has also been proved by the combustion scientists that flame stabilization is dependent on the location of the fuel injection and the flow stagnation temperature. Most of the open literatures reveals open cavity-based injection studies in two-dimensional combustors and studies in axisymmetric models are scant [12] [13].…”

The Implication of Injection Locations in an Axisymmetric Cavity-Based Scramjet Combustor

“…The configuration consists of an axisymmetric combustor with a cavity as shown in Figure 1 [33]. The diameter of the inlet is 26 mm, and the whole length of the combustor is 135 mm.…”

The Combustion Characteristics of Double Ramps in a Strut-Based Scramjet Combustor

“…A robust flame holding mechanism is needed owing to the short residence time of airflow in the scramjet combustor. There are various injection and flame holding mechanisms, such as cavities [4][5][6][7][8][9][10], pylons [11][12][13][14] and struts [15][16][17][18][19][20][21][22][23][24][25][26][27][28]. The combinations of the aforementioned schemes [29][30][31][32] were succeeded to some extend by several studies.…”