Small-scale Gaseous Oxygen Hybrid Rocket Testing Facility Upgrades for Regression Rate and Combustion Efficiency Studies

2018 ◽  
Author(s):  
Flora S. Mechentel ◽  
Brian J. Cantwell
Keyword(s):  
Combustion Efficiency ◽  
Small Scale ◽  
Hybrid Rocket ◽  
Gaseous Oxygen ◽  
Regression Rate ◽  
Testing Facility

scholarly journals Experimental Investigation on Combustion Characteristics of Hybrid Rocket Fuels with Multi-Angle Diverging Injector

2020 ◽  
Vol 5 (2) ◽  
pp. 12
Author(s):  
Pragya Berwal ◽  
Shelly Biswas
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Combustion Process ◽  
Combustion Efficiency ◽  
Heat Fluxes ◽  
Paraffin Wax ◽  
Hybrid Rocket ◽  
Gaseous Oxygen ◽  
Regression Rate ◽  
Fuel Surface

Injection pattern of the oxidizer injected into the combustion chamber is a significant factor in evaluating the performance of a hybrid rocket. In the hybrid rocket combustion process, oxidizer flows over the solid fuel grain surface, leading to a turbulent diffusion boundary layer formation and the flame is established inside the boundary layer. The heat transfer from flame to the fuel surface leads to pyrolysis of the fuel. The heat fluxes, due to pyrolysis, block the heat transfer further to the fuel surface, thus reducing the fuel regression rate. An attempt has been made in this paper to design and study the effect of the multi-angle diverging injector on the enhancement of the fuel regression rate and combustion efficiency of the hybrid rocket. The designed injector was compared with a shower head injector i.e., axial injector. The fuels used were paraffin wax and polyvinyl chloride (PVC) with gaseous oxygen as oxidizer. The effect of formation of the re-circulation zone and flow velocity were studied numerically by a cold flow simulation using ANSYS-Fluent software. It has been observed that direct impingement of the multi-angle diverging injector produces velocity in three directions, leading to distortion of the boundary layer. An increase of 8% in the average fuel regression rate for PVC fuel grain and 36.14% for paraffin wax fuel grain was observed, as compared to the shower head injector for the same oxidizer mass flow rate. A combustion efficiency increase of 38% and 14% was also observed using multi-angle diverging injector for PVC and paraffin wax fuel grains, respectively. A reduction in sliver and uniform fuel consumption was also observed using the novel multi-angle diverging injector.

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).

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.

scholarly journals Large-Scale CAMUI Type Hybrid Rocket Motor Scaling, Modeling, and Test Results

Aerospace ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 1
Author(s):  
Tor Viscor ◽  
Landon Kamps ◽  
Kazuo Yonekura ◽  
Hikaru Isochi ◽  
Harunori Nagata
Keyword(s):  
Regression Models ◽  
Large Scale ◽  
Rocket Motor ◽  
Small Scale ◽  
Test Results ◽  
Research Institutions ◽  
Hybrid Rocket ◽  
Regression Rate ◽  
Hybrid Rocket Motor

An understanding of the scalability of hybrid rocket regression models is critical for the enlargement and commercialization of small-scale engines developed within universities and similar research institutions. This paper investigates the fuel regression rates of recent 40 kN thrust-class motor experiments, which were designed based on fuel regression rate correlations of 2.5 kN thrust-class motors from previous research. The results show that fuel regression rates of the 40 kN experiments were within 26% of predictions made using correlations based on 2.5 kN experiments.

scholarly journals Modeling of gas–surface interface for paraffin-based hybrid rocket fuels in computational fluid dynamics simulations

2019 ◽  
Author(s):  
D. Bianchi ◽  
F. Nasuti ◽  
D. Delfini
Keyword(s):  
Numerical Simulations ◽  
Rocket Engine ◽  
Combustion Process ◽  
Operating Conditions ◽  
Hybrid Rocket ◽  
Gaseous Oxygen ◽  
Regression Rate ◽  
Surface Mass ◽  
Layer Interface ◽  
Inverse Power Law

Numerical simulations of the flowfield in a hybrid rocket engine are carried out with a multispecies chemically reacting Reynolds-averaged Navier–Stokes (RANS) solver which includes detailed gas–surface interaction (GSI) modeling based on surface mass and energy balances. The oxidizer is gaseous oxygen which is homogeneously fed into single-port cylindrical grains. The modeling of GSI already developed and validated for pyrolyzing fuels such as hydroxyl-terminated polybutadiene (HTPB), is extended to the case of liquefying fuels, such as paraffin wax. A simplified two-step global reaction mechanism is considered for the gas-phase chemistry to model the combustion process inside the chamber. Numerical simulations performed at different gas/melt-layer interface temperatures and oxygen mass fluxes show a considerable increase of fuel regression rate, in the range of 3 up to 5 times, for the liquefying fuel with respect to the pyrolyzing one. Results show that the regression rate enhancement is significant only when the gas/melt-layer interface of the liquefying fuel is close to the melting temperature. At increasing gas/melt-layer interface temperatures, the regression rate decreases following an inverse power law and gets close to that of a pyrolyzing fuel for the same operating conditions. Finally, regression rate behavior at varying oxygen mass flux of liquefying fuels is not substantially altered from that of pyrolyzing fuels as the oxidizer flux exponent remains rather constant.

scholarly journals Experimental Study of the Swirling Oxidizer Flow in HTPB/N2O Hybrid Rocket Motor

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Mohammad Mahdi Heydari ◽  
Nooredin Ghadiri Massoom
Keyword(s):  
Specific Impulse ◽  
Axial Flow ◽  
Combustion Efficiency ◽  
Swirl Flow ◽  
Rocket Motor ◽  
Outer Diameter ◽  
Hybrid Rocket ◽  
Feed System ◽  
Regression Rate ◽  
Hybrid Rocket Motor

Effects of swirling oxidizer flow on the performance of a HTPB/N2O Hybrid rocket motor were studied. A hybrid propulsion laboratory has been developed, to characterize internal ballistics characteristics of swirl flow hybrid motors and to define the operating parameters, like fuel regression rate, specific impulse, and characteristics velocity and combustion efficiency. Primitive variables, like pressure, thrust, temperature, and the oxidizer mass flow rate, were logged. A modular motor with 70 mm outer diameter and variable chamber length is designed for experimental analysis. The injector module has four tangential injectors and one axial injector. Liquid nitrous oxide (N2O) as an oxidizer is injected at the head of combustion chamber into the motor. The feed system uses pressurized air as the pressurant. Two sets of tests have been performed. Some tests with axial and tangential oxidizer injection and a test with axial oxidizer injection were done. The test results show that the fuel grain regression rate has been improved by applying tangential oxidizer injection at the head of the motor. Besides, it was seen that combustion efficiency of motors with the swirl flow was about 10 percent more than motors with axial flow.

Fuel Regression Rate in Hydroxyl-Terminated-Polybutadiene/Gaseous-Oxygen Hybrid Rocket Motors

2001 ◽  
Vol 17 (1) ◽  
pp. 35-42 ◽  
Author(s):  
Philmon George ◽  
S. Krishnan ◽  
P. M. Varkey ◽  
M. Ravindran ◽  
Lalitha Ramachandran
Keyword(s):  
Hybrid Rocket ◽  
Gaseous Oxygen ◽  
Regression Rate ◽  
Rocket Motors
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