Combustion performances of pure hydrogen in an experimental trapped vortex combustor have been tested underdifferent operating conditions. Pressure fluctuations, NOx emissions, OH distributions, and LBO (Lean Blow Out...Combustion performances of pure hydrogen in an experimental trapped vortex combustor have been tested underdifferent operating conditions. Pressure fluctuations, NOx emissions, OH distributions, and LBO (Lean Blow Out)were measured in the tests. Results indicate that the TVC test rig has successfully realized a double vortex constructionin the cavity zone in a wide range of flow conditions. Hydrogen combustion in the test rig has achievedan excellent LBO performance and relatively low NOx emissions. Through comparison of dynamic pressure data,OH fluctuation images, and NOx emissions, the optimal operating condition has been found out to be Φp=0.4,fuel split=0.4, and primary air/fuel premixed.展开更多
A trapped vortex combustor （TVC） has been a very promising novel concept for it offers improvements in lean blow out, altitude relight, operating range, as well as a potential to decrease NOx emissions compared to c...A trapped vortex combustor （TVC） has been a very promising novel concept for it offers improvements in lean blow out, altitude relight, operating range, as well as a potential to decrease NOx emissions compared to conventional combustors. The present paper discusses the improved designs of the new combustor over the prior ones of our research group, including that：a） the over-all dimensions, both axial and radial, are reduced to those of an actual aero-engine combustor; b） the air flow distribution is optimized, and especially 15% of the air is fed into the liner as cooling air; c） a straight-wall diffuser with divergence angle 9°is added. A series of experiments （cavity-fueled only, under atmospheric pressure） has been conducted to investigate the performance of the improved TVC. Experimental results show that at the inlet temperature of 523 K, the inlet pressure of 0.1 MPa, stable operation of the TVC test rig is observed for the Mach number 0.15-0.34, indicating good flame stability; the combustion efficiency obtained in this paper falls into the range of 60%-96%; as the total excess air ratio increases, the combustion efficiency decreases, while the increase of the inlet temperature is beneficial to high combustion efficiency; besides, the optimal Mach numbers for high combustion efficiency under different inlet conditions are confirmed. The outlet temperature profiles feature a bottom in the midheight of the exit. This paper demonstrates the feasibility for the TVC to be applied to a realistic aero-engine preliminarily and provides reference for TVC design.展开更多
Trapped vortex combustor （TVC） is an advanced low-pollution gas turbine combustor, with the adoption of staged combustion technique. To achieve low-pollutant emission and better combustion performance, the proportio...Trapped vortex combustor （TVC） is an advanced low-pollution gas turbine combustor, with the adoption of staged combustion technique. To achieve low-pollutant emission and better combustion performance, the proportion of the air flow in each combustion zone should be precisely determined in the design of the combustor. Due to the presence of entrainment phenomenon, the total air flow in the cavity zone is difficult to estimate. To overcome the measurement difficulty, this study adopts the indirect measurement approach in the experimental research of entrainment phenomenon in the cavity. In accordance with the measurement principle, a TVC model fueled by methane is designed. Under two experimental conditions, i.e. with and without direct air intake in the cavity, the influence of the mainstream air flow velocity, the air intake velocity in the cavity, the height of inlet channel, the structure of holder and the structural proportion of the cavity on entrainment in the cavity is studied, respectively, through experiment at atmospheric temperature and pressure. The results suggest that the air flow velocity of mainstream, the air intake velocity of the cavity and the structure of the holder exert significant influence on the air entrainment, while the influence of structural proportion of the cavity is comparatively insignificant. The square root of momentum ratio of cavity air to mainstream air could be used to analyze the correlation of the entrainment data.展开更多
基金National Natural Science Foundation of China (No. 50576098)the National High Technology R&D Project of China (No.2006AA05A104)
文摘Combustion performances of pure hydrogen in an experimental trapped vortex combustor have been tested underdifferent operating conditions. Pressure fluctuations, NOx emissions, OH distributions, and LBO (Lean Blow Out)were measured in the tests. Results indicate that the TVC test rig has successfully realized a double vortex constructionin the cavity zone in a wide range of flow conditions. Hydrogen combustion in the test rig has achievedan excellent LBO performance and relatively low NOx emissions. Through comparison of dynamic pressure data,OH fluctuation images, and NOx emissions, the optimal operating condition has been found out to be Φp=0.4,fuel split=0.4, and primary air/fuel premixed.
基金Aeronautical Science Foundation of China (2008ZB52013)Funding of Jiangsu Innovation Program for Graduate Education (CXLX11_0211)
文摘A trapped vortex combustor （TVC） has been a very promising novel concept for it offers improvements in lean blow out, altitude relight, operating range, as well as a potential to decrease NOx emissions compared to conventional combustors. The present paper discusses the improved designs of the new combustor over the prior ones of our research group, including that：a） the over-all dimensions, both axial and radial, are reduced to those of an actual aero-engine combustor; b） the air flow distribution is optimized, and especially 15% of the air is fed into the liner as cooling air; c） a straight-wall diffuser with divergence angle 9°is added. A series of experiments （cavity-fueled only, under atmospheric pressure） has been conducted to investigate the performance of the improved TVC. Experimental results show that at the inlet temperature of 523 K, the inlet pressure of 0.1 MPa, stable operation of the TVC test rig is observed for the Mach number 0.15-0.34, indicating good flame stability; the combustion efficiency obtained in this paper falls into the range of 60%-96%; as the total excess air ratio increases, the combustion efficiency decreases, while the increase of the inlet temperature is beneficial to high combustion efficiency; besides, the optimal Mach numbers for high combustion efficiency under different inlet conditions are confirmed. The outlet temperature profiles feature a bottom in the midheight of the exit. This paper demonstrates the feasibility for the TVC to be applied to a realistic aero-engine preliminarily and provides reference for TVC design.
文摘Trapped vortex combustor （TVC） is an advanced low-pollution gas turbine combustor, with the adoption of staged combustion technique. To achieve low-pollutant emission and better combustion performance, the proportion of the air flow in each combustion zone should be precisely determined in the design of the combustor. Due to the presence of entrainment phenomenon, the total air flow in the cavity zone is difficult to estimate. To overcome the measurement difficulty, this study adopts the indirect measurement approach in the experimental research of entrainment phenomenon in the cavity. In accordance with the measurement principle, a TVC model fueled by methane is designed. Under two experimental conditions, i.e. with and without direct air intake in the cavity, the influence of the mainstream air flow velocity, the air intake velocity in the cavity, the height of inlet channel, the structure of holder and the structural proportion of the cavity on entrainment in the cavity is studied, respectively, through experiment at atmospheric temperature and pressure. The results suggest that the air flow velocity of mainstream, the air intake velocity of the cavity and the structure of the holder exert significant influence on the air entrainment, while the influence of structural proportion of the cavity is comparatively insignificant. The square root of momentum ratio of cavity air to mainstream air could be used to analyze the correlation of the entrainment data.
