What is a cavity based scramjet?
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A cavity-based scramjet is a type of scramjet engine design that utilizes a cavity as a flame holder for efficient mixing between air and fuel . The cavity is a well-organized method for supporting the ignition zone and improving the performance of the scramjet combustor . The cavity typically has a slanted rear wall and is combined with transverse fuel injection in supersonic combustors . The presence of a cavity in the scramjet combustor helps to create a subsonic environment that facilitates flame ignition and stabilization . The cavity also plays a role in enhancing combustion by providing a space for efficient burning of the fuel-air mixture . Recent research has explored different aspects of cavity-based injection schemes, including variations in cavity shape, location of fuel/air injection, and the use of dual cavities . Overall, the cavity-based scramjet design is aimed at improving the efficiency and performance of scramjet engines for hypersonic flight vehicles .
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| Papers (4) | Insight |
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| A cavity-based scramjet is a type of scramjet combustor that uses a cavity with a slanted rear wall as a flame holding device. | |
138 Citations | A cavity-based scramjet is a type of scramjet engine that uses a cavity flame holder for efficient mixing of air and fuel. |
27 Citations | A cavity-based scramjet is a type of combustor configuration used in scramjet engines, which are air-breathing engines for high-speed flight. |
| A cavity-based scramjet is a type of scramjet combustor that uses a cavity to stabilize the combustion process. |
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What are the effects of buoyancy-driven flow on the irregular shape geometry of cavity?5 answersBuoyancy-driven flow in irregular-shaped cavities has several effects. The shape change, such as varying the slope angle of the heated wall, can lead to important changes in the thermal and dynamic flow patterns. The presence of irregular-shaped heating bodies, such as diamond elliptic arrays or horizontal and vertical elliptic heating bodies, can also affect the flow regime and transition from unsteady to steady state. Additionally, the buoyancy generated due to non-uniform heating and the movement of the top wall can result in the growth of upstream and downstream secondary eddies, as well as the formation of large recirculation regions. The inclusion of a magnetic field with an angle to the horizontal axis in an open cavity can further influence the flow and temperature profiles. Overall, the irregular shape geometry of the cavity plays a significant role in determining the flow patterns and heat transfer characteristics.
What is the importance of cavity based scramjet injection?3 answersCavity-based injection in scramjet combustors is important for enhancing combustion performance and improving the overall efficiency of the engine. The use of cavity-based injections, such as angled and transverse injections, creates strong shock trains in the cavity region, leading to enhanced combustion of the fuel-air mixture. Additionally, cavity designs with wavy walls and additional cavities increase the stability of combustion by increasing the residence time of the airstream and creating more recirculation regions. The allocation of fuel injection between transverse injectors and the duct wall upstream of the cavity also affects combustion characteristics, with increased strut injection leading to improved thrust increment and specific impulse. Furthermore, multi-staged injection, including both strut and wall injections, enhances the wall pressure profile along the combustor without upstream propagation of pressure rise. Overall, cavity-based injection techniques play a crucial role in optimizing the performance of scramjet combustors by improving combustion efficiency and enhancing mixing of fuel and air.
What are the current challenges to the development of scramjet engines?2 answersThe current challenges to the development of scramjet engines include inefficient combustion due to the low residence time of air inside the combustor, the need to ignite and maintain ignition of the air-fuel mixture at high speeds, complex flow inside the scramjet combustor requiring a better understanding of turbulence, boundary layer formation and separation, and physiochemical processes involved in combustion, and the need for proper air-fuel mixing to improve the efficiency of the engine. Other challenges include improving the mixing efficiency and combustion performance through different fuel injection techniques and types of fuel, and addressing obstacles such as high heat fluxes, pressure loads, shock-wave-boundary-layer interactions, and choked flow inside the isolator channel during scramjet design.
How can upstream injection be used to improve the performance of a scramjet cavity with hydrogen fuel?1 answersUpstream injection can be used to improve the performance of a scramjet cavity with hydrogen fuel by enhancing mixing efficiency and fuel dispersion. Several studies have investigated different injection structures and geometries to achieve this improvement. The use of elliptical nozzles, both single and two-stage, has been found to significantly improve the ignition and combustion of the fuel-rich mixture. Crescent-shaped cavities placed upstream of the fuel injector have also been shown to enhance mixing through vorticity generation, resulting in increased mixing efficiency. Additionally, the effects of fuel injection angle on mixing parameters have been studied, with transverse injection showing deeper fuel jet penetration and angled injection demonstrating better mixing capability. Furthermore, the role of the upstream step condition on mixing efficiency has been investigated, with the downstream mixing efficiency improving as the jet space increases.