scholarly journals Experimental Investigation of the Continuous Transition of Flame-Spreading near the Blow-Off Limit

2020 ◽  
Vol 2020 ◽  
pp. 1-7 ◽  
Author(s):  
K. Komizu ◽  
Y. Saito ◽  
A. Tsuji ◽  
H. Nagata
Keyword(s):  
Diffusion Flame ◽  
Axial Direction ◽  
Forced Flow ◽  
Hybrid Rocket ◽  
Threshold Velocity ◽  
Continuous Transition ◽  
Gaseous Oxygen ◽  
Flame Spreading ◽  
Opposed Flow ◽  
Upstream Direction

This study investigates the continuous transition from flame-spreading to stabilized combustion near the blow-off limit in opposed forced flow by using expanding solid fuel duct that makes distribution of oxidizer velocity in the axial direction. The stabilized combustion is a diffusion flame that appears in the Axial-Injection End-Burning Hybrid Rocket. The boundary between flame-spreading and stabilized combustion has not been investigated in detail. Polymethyl methacrylate (PMMA) rectangular ducts were used as a fuel, and gaseous oxygen was used as an oxidizer. All firing tests were conducted at atmospheric pressure. The diffusion flame traveled in the opposed-flow field where the oxidizer velocity increases continuously in the upstream direction. The combustion mode changed when oxidizer velocity at the flame tip exceeded a certain value. The oxidizer velocity used in this experiment ranges from 0.6 to 32.8 m/s. Experimental results show that a threshold oxidizer velocity of the transition can be determined. In this study, the threshold velocity was 26.4 m/s.

scholarly journals Opposed flow diffusion flame extensions

1981 ◽  
Vol 18 (1) ◽  
pp. 1853-1860 ◽  
Author(s):  
C.M. Kinoshita ◽  
P.J. Pagni ◽  
R.A. Beier
Keyword(s):  
Diffusion Flame ◽  
Opposed Flow

Estimation of Blow-off Limit for Flame Spreading over Electric Wires in High Opposed Flow Field

2019 ◽  
Vol 2019 (0) ◽  
pp. J19104P
Author(s):  
Hiroki SATO ◽  
Yusuke KONNO ◽  
Nozomu HASHIMOTO ◽  
Osamu FUJITA
Keyword(s):  
Flow Field ◽  
Flame Spreading ◽  
Opposed Flow

Conceptual Regenerative Nozzle Cooling Design for a Hydroxyl-Terminated Polybutadiene and Oxygen Hybrid Rocket Engine

2017 ◽  
Author(s):  
Luis R. Robles ◽  
Johnny Ho ◽  
Bao Nguyen ◽  
Geoffrey Wagner ◽  
Jeremy Surmi ◽  
...  
Keyword(s):  
Combustion Chamber ◽  
High Temperatures ◽  
Cooling System ◽  
Rocket Engine ◽  
Combustion Efficiency ◽  
Rocket Engines ◽  
Hybrid Rocket ◽  
Gaseous Oxygen ◽  
Rocket Nozzle ◽  
Regenerative Cycle

Regenerative rocket nozzle cooling technology is well developed for liquid fueled rocket engines, but the technology has yet to be widely applied to hybrid rockets. Liquid engines use fuel as coolant, and while the oxidizers typically used in hybrids are not as efficient at conducting heat, the increased renewability of a rocket using regenerative cycle should still make the technology attractive. Due to the high temperatures that permeate throughout a rocket nozzle, most nozzles are predisposed to ablation, supporting the need to implement a nozzle cooling system. This paper presents a proof-of-concept regenerative cooling system for a hybrid engine which uses hydroxyl-terminated polybutadiene (HTPB) as its solid fuel and gaseous oxygen (O2) as its oxidizer, whereby a portion of gaseous oxygen is injected directly into the combustion chamber and another portion is routed up through grooves on the exterior of a copper-chromium nozzle and, afterwards, injected into the combustion chamber. Using O2 as a coolant will significantly lower the temperature of the nozzle which will prevent ablation due to the high temperatures produced by the exhaust. Additional advantages are an increase in combustion efficiency due to the heated O2 being used for combustion and an increased overall efficiency from the regenerative cycle. A computational model is presented, and several experiments are performed using computational fluid dynamics (CFD).

scholarly journals Chemical kinetic modeling of dimethyl carbonate in an opposed-flow diffusion flame

2005 ◽  
Vol 30 (1) ◽  
pp. 1111-1118 ◽  
Author(s):  
Pierre A. Glaude ◽  
William J. Pitz ◽  
Murray J. Thomson
Keyword(s):  
Kinetic Modeling ◽  
Diffusion Flame ◽  
Dimethyl Carbonate ◽  
Chemical Kinetic ◽  
Opposed Flow

Regression rate performance of paraffin wax and bees wax –Gox with varied grain configuration in a hybrid rocket motor

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Saravanan G. ◽  
Shanmugam S. ◽  
Veerappan A.R.
Keyword(s):  
Mass Flux ◽  
Design Methodology ◽  
Paraffin Wax ◽  
Chamber Pressure ◽  
Solid Fuels ◽  
Hybrid Rocket ◽  
Local Regression ◽  
Gaseous Oxygen ◽  
Regression Rate ◽  
Content Type

Purpose This paper aims to determine the regression rate using wax fuels for three different grain configurations and find a suitable grain port design for hybrid rocket application. Design/methodology/approach The design methodology of this work includes different grain port designs and subsequent selection of solid fuels for a suitable hybrid rocket application. A square, a cylindrical and a five-point star grained were designed and prepared using paraffin and beeswax fuels. They were tested in a laboratory-scale rocket with gaseous oxygen to study the effectiveness of solid fuels on these grain structures. The regression rate by static fire testing of these wax fuels was analyzed. Findings Beeswax performance is better than that of paraffin wax fuel for all three designs, and the five-slotted star fuel port grain attained the best performance. Beeswax fuel attained an average regression rate ≈of 1.35 mm/s as a function of oxidizer mass flux Gox ≈ 111.8 kg/m2 s and for paraffin wax 1.199 mm/s at Gox ≈ 121 kg/m2 s with gaseous oxygen. The local regression rates of fuels increased in the range of 0.93–1.194 mm/s at oxidizer mass flux range of 98–131 kg/m2 s for cylindrical grain, 0.99–1.21 mm/s at oxidizer mass flux range of 96–129 kg/m2s for square grain and 1.12–1.35 mm/s at oxidizer mass flux range of 91–126 kg/m2 s for a star grain. A complete set of the regression rate formulas is obtained for all three-grain designs as a function of oxidizer flux rate. Research limitations/implications The experiment has been performed for a lower chamber pressure up to 10 bar. Originality/value Different grain configurations were designed according to the required dimension of the combustion chamber, injector and exhaust nozzle of the design of a lab-scale hybrid rocket, and input parameters were selected and analyzed.

Testing of Paraffin-based Hybrid Rocket Fuel using Gaseous Oxygen Oxidiser

2012 ◽  
Vol 62 (5) ◽  
pp. 277-283 ◽  
Author(s):  
Yash Pal ◽  
J. Baskar ◽  
S. Murugesan
Keyword(s):  
Hybrid Rocket ◽  
Rocket Fuel ◽  
Gaseous Oxygen
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