Evaluation of Combustion Chamber Pressure of 1N-Class Green Monopropellant Thruster with Discharge Plasma System

2017 ◽  
Vol 65 (3) ◽  
pp. 117-122
Author(s):  
Asato WADA ◽  
Hiroshi MAEDA ◽  
Takahiro SHINDO ◽  
Hiroki WATANABE ◽  
Haruki TAKEGAHARA
2019 ◽  
Vol 12 (3) ◽  
pp. 262-271
Author(s):  
T.N. Rajesh ◽  
T.J.S. Jothi ◽  
T. Jayachandran

Background: The impulse for the propulsion of a rocket engine is obtained from the combustion of propellant mixture inside the combustion chamber and as the plume exhausts through a convergent- divergent nozzle. At stoichiometric ratio, the temperature inside the combustion chamber can be as high as 3500K. Thus, effective cooling of the thrust chamber becomes an essential criterion while designing a rocket engine. Objective: A new cooling method of thrust chambers was introduced by Chiaverni, which is termed as Vortex Combustion Cold-Wall Chamber (VCCW). The patent works on cyclone separators and confined vortex flow mechanism for providing high propellant mixing with improved degree of turbulence inside the combustion chamber, providing the required notion for studies on VCCW. The flow inside a VCCW has a complex structure characterised by axial pressure losses, swirl velocities, centrifugal force, flow reversal and strong turbulence. In order to study the flow phenomenon, both the experimental and numerical investigations are carried out. Methods: In this study, non-reactive flow analysis was conducted with real propellants like gaseous oxygen and hydrogen. The test was conducted to analyse the influence of mixture ratio and injection pressure of the propellants on the chamber pressure in a vortex combustion chamber. A vortex combustor was designed in which the oxidiser injected tangentially at the aft end near the nozzle spiraled up to the top plate and formed an inner core inside the chamber. The fuel was injected radially from injectors provided near the top plate and the propellants were mixed in the inner core. This resulted in enhanced mixing and increased residence time for the fuel. More information on the flow behaviour has been obtained by numerical analysis in Fluent. The test also investigated the sensitivity of the tangential injection pressure on the chamber pressure development. Results: All the test cases showed an increase in chamber pressure with the mixture ratio and injection pressure of the propellants. The maximum chamber pressure was found to be 3.8 bar at PC1 and 2.7 bar at PC2 when oxidiser to fuel ratio was 6.87. There was a reduction in chamber pressure of 1.1 bar and 0.7 bar at PC1 and PC2, respectively, in both the cases when hydrogen was injected. A small variation in the pressure of the propellant injected tangentially made a pronounced effect on the chamber pressure and hence vortex combustion chamber was found to be very sensitive to the tangential injection pressure. Conclusion: VCCW mechanism has been to be found to be very effective for keeping the chamber surface within the permissible limit and also reducing the payload of the space vehicle.


2016 ◽  
Vol 80 ◽  
pp. 69-75 ◽  
Author(s):  
Huijuan Wang ◽  
Guangshun Zhou ◽  
He Guo ◽  
Zhaoyi Ge ◽  
Chengwu Yi

Author(s):  
Kweonha Park

Liquefied petroleum gas (LPG) sprays and diffusion flames are investigated in a constant volume combustion chamber having an impingement plate. The spray and flame images are visualized and compared with diesel and gasoline images over a wide range of ambient pressure. The high-speed digital camera is used to take the flame images. The injection pressure is generated by a Haskel air-driven pump, and the initial chamber pressure is adjusted by the amount of pumping air. The LPG spray and flame photographs are compared with those of gasoline and diesel fuel at the same conditions, and then the spray and flame development behaviour is analysed. The spray photographs show that the dispersion characteristics of LPG spray are sensitive to the ambient pressure. In a low initial chamber pressure LPG fuel in the liquid phase evaporates quickly and does not reach down easily to the impinging plate having a hot coil for ignition. That makes the temperature and equivalence ratio low near the ignition coil, thus making ignition diffcult. On the other hand, in a high initial chamber pressure the spray leaving the nozzle gathers around the ignition site after impinging on the plate, which makes an intense flame near the plate. If applied to small-sized direct injection engines that are not able to avoid spray impinging on a cylinder wall, LPG will have faster and cleaner combustion than diesel or gasoline fuels. However, the chamber geometry should be carefully designed to enable a sufficient amount of vaporized fuel to get to the ignition site


2018 ◽  
Vol 10 (1) ◽  
pp. 168781401774805
Author(s):  
Yinli Xiao ◽  
Zupeng Wang ◽  
Zhengxin Lai ◽  
Kefei Chen ◽  
Wenyan Song

The principal features of primary zone determine the performance parameters of the whole combustion chamber, such as the pollutant emissions and combustion efficiency. In this work, flow field and major species concentration measurements are conducted in the primary zone of an aero-engine combustion chamber. The operating conditions such as air inlet temperature, chamber pressure, and air-to-fuel ratio are chosen to replicate the realistic operating conditions. The velocity field and streamlines are obtained by particle imaging velocimetry technology. The concentrations of major species are acquired by a spontaneous Raman scattering system. This article validates the feasibility of two laser diagnostic measurement techniques and presents the initial results under realistic aero-engine conditions.


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