Experimental Study of Spray and Combustion Characteristics in Gas-Centered Swirl Coaxial Injectors: Influence of Recess Ratio and Gas Swirl
The spray and combustion characteristics of a gas-centered swirl coaxial (GCSC) injector used in oxidizer-rich staged combustion cycle engines were analyzed. The study focused on varying the recess ratio, presence of gas swirl, and swirl direction to improve injector performance. The impact of the r...
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MDPI AG
2024-03-01
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| author | Jungho Lee Ingyu Lee Seongphil Woo Yeoungmin Han Youngbin Yoon |
| author_facet | Jungho Lee Ingyu Lee Seongphil Woo Yeoungmin Han Youngbin Yoon |
| author_sort | Jungho Lee |
| collection | DOAJ |
| description | The spray and combustion characteristics of a gas-centered swirl coaxial (GCSC) injector used in oxidizer-rich staged combustion cycle engines were analyzed. The study focused on varying the recess ratio, presence of gas swirl, and swirl direction to improve injector performance. The impact of the recess ratio was assessed by increasing it for gas jet-type injectors with varying momentum ratios. Gas-swirl effects were studied by comparing injectors with and without swirl against a baseline of a low recess ratio gas injection. In atmospheric pressure-spray experiments, injector performance was assessed using backlight photography, cross-sectional imaging with a structured laser illumination planar imaging technique (SLIPI), and droplet analysis using ParticleMaster. Increasing the recess ratio led to reduced spray angle and droplet size, and trends of gas swirl-type injectors were similar to those of high recess ratio gas jet-type injectors. Combustion tests involved fabricating combustion chamber heads equipped with identical injectors, varying only the injector type. Oxidizer-rich combustion gas, produced by a pre-burner, and kerosene served as propellants. Combustion characteristics, including characteristic velocity, combustion efficiency, and heat flux, were evaluated. Elevated recess ratios correlated with increased characteristic velocity and reduced differences in the momentum–flux ratios of injectors. However, increasing the recess ratio yielded diminishing returns on combustion efficiency enhancement beyond a certain threshold. Gas swirling did not augment characteristic velocity but notably influenced heat flux distribution. The trends observed in spray tests were related to combustion characteristics regarding heat flux and combustion efficiency. Additionally, it was possible to estimate changes in the location and shape of the flame according to the characteristics of the injector. |
| first_indexed | 2024-04-24T18:39:52Z |
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| id | doaj.art-6a0923667ade4850a62d7ad41439d12a |
| institution | Directory Open Access Journal |
| issn | 2226-4310 |
| language | English |
| last_indexed | 2024-04-24T18:39:52Z |
| publishDate | 2024-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Aerospace |
| spelling | doaj.art-6a0923667ade4850a62d7ad41439d12a2024-03-27T13:15:40ZengMDPI AGAerospace2226-43102024-03-0111320910.3390/aerospace11030209Experimental Study of Spray and Combustion Characteristics in Gas-Centered Swirl Coaxial Injectors: Influence of Recess Ratio and Gas SwirlJungho Lee0Ingyu Lee1Seongphil Woo2Yeoungmin Han3Youngbin Yoon4Department of Aerospace Engineering, Seoul National University, Seoul 08826, Republic of KoreaDepartment of Aerospace Engineering, Seoul National University, Seoul 08826, Republic of KoreaKorea Aerospace Research Institute, Daejeon 34133, Republic of KoreaKorea Aerospace Research Institute, Daejeon 34133, Republic of KoreaDepartment of Aerospace Engineering, Seoul National University, Seoul 08826, Republic of KoreaThe spray and combustion characteristics of a gas-centered swirl coaxial (GCSC) injector used in oxidizer-rich staged combustion cycle engines were analyzed. The study focused on varying the recess ratio, presence of gas swirl, and swirl direction to improve injector performance. The impact of the recess ratio was assessed by increasing it for gas jet-type injectors with varying momentum ratios. Gas-swirl effects were studied by comparing injectors with and without swirl against a baseline of a low recess ratio gas injection. In atmospheric pressure-spray experiments, injector performance was assessed using backlight photography, cross-sectional imaging with a structured laser illumination planar imaging technique (SLIPI), and droplet analysis using ParticleMaster. Increasing the recess ratio led to reduced spray angle and droplet size, and trends of gas swirl-type injectors were similar to those of high recess ratio gas jet-type injectors. Combustion tests involved fabricating combustion chamber heads equipped with identical injectors, varying only the injector type. Oxidizer-rich combustion gas, produced by a pre-burner, and kerosene served as propellants. Combustion characteristics, including characteristic velocity, combustion efficiency, and heat flux, were evaluated. Elevated recess ratios correlated with increased characteristic velocity and reduced differences in the momentum–flux ratios of injectors. However, increasing the recess ratio yielded diminishing returns on combustion efficiency enhancement beyond a certain threshold. Gas swirling did not augment characteristic velocity but notably influenced heat flux distribution. The trends observed in spray tests were related to combustion characteristics regarding heat flux and combustion efficiency. Additionally, it was possible to estimate changes in the location and shape of the flame according to the characteristics of the injector.https://www.mdpi.com/2226-4310/11/3/209staged-combustion-cycle rocket enginegas-centered swirl coaxial injectorrecess ratiogas swirlspray characteristicscombustion efficiency |
| spellingShingle | Jungho Lee Ingyu Lee Seongphil Woo Yeoungmin Han Youngbin Yoon Experimental Study of Spray and Combustion Characteristics in Gas-Centered Swirl Coaxial Injectors: Influence of Recess Ratio and Gas Swirl Aerospace staged-combustion-cycle rocket engine gas-centered swirl coaxial injector recess ratio gas swirl spray characteristics combustion efficiency |
| title | Experimental Study of Spray and Combustion Characteristics in Gas-Centered Swirl Coaxial Injectors: Influence of Recess Ratio and Gas Swirl |
| title_full | Experimental Study of Spray and Combustion Characteristics in Gas-Centered Swirl Coaxial Injectors: Influence of Recess Ratio and Gas Swirl |
| title_fullStr | Experimental Study of Spray and Combustion Characteristics in Gas-Centered Swirl Coaxial Injectors: Influence of Recess Ratio and Gas Swirl |
| title_full_unstemmed | Experimental Study of Spray and Combustion Characteristics in Gas-Centered Swirl Coaxial Injectors: Influence of Recess Ratio and Gas Swirl |
| title_short | Experimental Study of Spray and Combustion Characteristics in Gas-Centered Swirl Coaxial Injectors: Influence of Recess Ratio and Gas Swirl |
| title_sort | experimental study of spray and combustion characteristics in gas centered swirl coaxial injectors influence of recess ratio and gas swirl |
| topic | staged-combustion-cycle rocket engine gas-centered swirl coaxial injector recess ratio gas swirl spray characteristics combustion efficiency |
| url | https://www.mdpi.com/2226-4310/11/3/209 |
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