Correction: Small-scale Gaseous Oxygen Hybrd Rocket Testing for Regression Rate and Combustion Efficiency Studies

2017 ◽  
Author(s):  
Flora S. Mechentel ◽  
A.M. Coates ◽  
Brian J. Cantwell
Keyword(s):  
Combustion Efficiency ◽  
Small Scale ◽  
Gaseous Oxygen ◽  
Regression Rate

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.

scholarly journals Metals and Alloys Additives as Enhancer for Rocket Propulsion: A Review

2021 ◽  
Vol 90 (1) ◽  
pp. 1-9
Author(s):  
Izham Izzat Ismail ◽  
Norhuda Hidayah Nordin ◽  
Muhammad Hanafi Azami ◽  
Nur Azam Abdullah
Keyword(s):  
Specific Impulse ◽  
Flame Temperature ◽  
High Energy ◽  
Combustion Efficiency ◽  
High Energy Density ◽  
Regression Rate ◽  
High Entropy ◽  
Rocket Propulsion ◽  
Wide Range ◽  
Metal Additives

A rocket's engine usually uses fuel and oxygen as propellants to increase the rocket's projection during launch. Nowadays, metallic ingredients are commonly used in the rocket’s operation to increase its performance. Metallic ingredients have a high energy density, flame temperature, and regression rate that are important factors in the propulsion process. There is a wide range of additives have been reported so far as catalysts for rocket propulsion. The studies show that the presence of metal additives improves the regression rate, specific impulse and combustion efficiency. Herein, the common energetic additives for rocket propulsion such as metal and light metals are reviewed. Besides the effect of these energetic particles on the regression behaviors of base (hybrid) fuel has been exclusively discussed. This paper also proposed a new alloy namely high entropy alloys (HEAs) as a new energetic additive that can potentially increase the performance of the rocket propellant system.

scholarly journals Influence of Polyisobutylene Kerosene Additive on Combustion Efficiency in a Liquid Propellant Rocket Engine

Aerospace ◽  
2019 ◽  
Vol 6 (12) ◽  
pp. 129 ◽  
Author(s):  
Igor Borovik ◽  
Evgeniy Strokach ◽  
Alexander Kozlov ◽  
Valeriy Gaponov ◽  
Vladimir Chvanov ◽  
...  
Keyword(s):  
Combustion Chamber ◽  
Film Cooling ◽  
Rocket Engine ◽  
Combustion Efficiency ◽  
Liquid Propellant ◽  
Gaseous Oxygen ◽  
Wall Film ◽  
Measurement Results ◽  
Liquid Propellant Rocket Engine ◽  
Propellant Rocket

The combustion of kerosene with the polymer additive polyisobutylene (PIB) was experimentally investigated. The aim of the study was to measure the effect of PIB kerosene on the efficiency of combustion chamber cooling and the combustion efficiency of the liquid propellant for a rocket engine operating on kerosene and gaseous oxygen (GOX). The study was conducted on an experimental rocket engine using kerosene wall film cooling in the combustion chamber. Fire tests showed that the addition of polyisobutylene to kerosene had no significant effect on the combustion efficiency. However, analysis of the wall temperature measurement results showed that the use of PIB kerosene is more effective for film cooling than pure kerosene, which can increase the efficiency of combustion chamber cooling and subsequently increase its reliability and reusability. Thus, the findings of this study are expected to be of use in further investigations of wall film cooling efficiency.

Experimental Analysis of an Ultra Compact Combustor Powered Turbine Engine

2019 ◽  
Author(s):  
Brian T. Bohan ◽  
Marc D. Polanka
Keyword(s):  
Engine Performance ◽  
Combustion Products ◽  
Combustion Efficiency ◽  
Small Scale ◽  
Engine Operation ◽  
Turbine Engine ◽  
Nozzle Guide ◽  
Nozzle Guide Vanes ◽  
Length Reduction ◽  
Outside Diameter

Abstract The innovative Ultra Compact Combustor (UCC) is an alternative to traditional turbine engine combustors and has been shown to reduce the combustor volume and offer potential improvements in combustion efficiency. Prior UCC configurations featured a circumferential combustion cavity positioned around the outside diameter (OD) of the engine. This configuration would be difficult to implement in a vehicle with a small, fixed diameter and had difficulty migrating the hot combustion products at the OD radially inward across an axial core flow to present a uniform temperature distribution to the first turbine stage. The present study experimentally tested a new UCC configuration that featured a circumferential cavity that exhausted axially into a dilution zone positioned just upstream of the nozzle guide vanes. The combustor was sized as a replacement burner for the JetCat P90 RXi small-scale turbine engine and fit inside the engine casing. This combustor configuration achieved a 33% length reduction compared to the stock JetCat combustor and achieved comparable engine performance across a limited operating range. Self-sustaining engine operation was achieved with a rotating compressor and turbine making this study the first to achieve operation of a UCC powered turbine engine.

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).

Development of a Small-Scale Catalytic Gas Turbine Combustor

1982 ◽  
Vol 104 (1) ◽  
pp. 52-57 ◽  
Author(s):  
S. J. Anderson ◽  
M. A. Friedman ◽  
W. V. Krill ◽  
J. P. Kesselring
Keyword(s):  
Steady State ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Combustion Efficiency ◽  
Small Scale ◽  
Time Interval ◽  
Nox Emissions ◽  
Fuel Injector ◽  
Gas Turbine Combustor ◽  
Opposed Jet

Catalytically supported thermal combustion can provide low NOx emissions with gaseous and distillate fuels while maintaining high combustion efficiency. For stationary gas turbines, catalytic combustion may be the only emerging technology that can cost effectively meet recent federal regulations for NOx emissions. Under EPA sponsorship, a small-scale, catalytic gas turbine combustor was developed to evaluate transient and steady state combustor performance. The combustor consisted of a multiple air-atomizing fuel injector, an opposed jet igniter, and a graded-cell monolithic reactor. System startup, including opposed jet ignition and catalyst stabilization, was achieved in 250 seconds. This time interval is comparable to conventional gas turbines. Steady state operation was performed at 0.505 MPa (5 atmospheres) pressure and 15.3 m/s (50 ft/s) reference velocities. Thermal NOx emissions were measured below 10 ppmv, while fuel NOx conversion ranged from 75 to 95 percent. At catalyst bed temperatures greater than 1422K (2100°F), total CO and UHC emissions were less than 50 ppmv indicating combustion efficiency greater than 99.9 percent. Compared with conventional gas turbine combustors, the catalytic reactor operates only within a relatively narrow range of fuel/air ratios. As a result, modified combustor air distribution or fuel staging will be required to achieve the wide turndown required in large stationary systems.

Experimental Analysis of an Ultra-Compact Combustor Powered Turbine Engine

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Brian T. Bohan ◽  
Marc D. Polanka
Keyword(s):  
Experimental Testing ◽  
Engine Performance ◽  
Combustion Products ◽  
Combustion Efficiency ◽  
Small Scale ◽  
Engine Operation ◽  
Turbine Engine ◽  
Nozzle Guide ◽  
Nozzle Guide Vanes ◽  
Length Reduction

Abstract The innovative ultra-compact combustor (UCC) is an alternative to traditional turbine engine combustors and has been shown to reduce the combustor length and offer potential improvements in combustion efficiency. Prior UCC configurations featured a circumferential combustion cavity positioned around the outside diameter (OD) of the engine. This configuration would be difficult to implement in a vehicle with a small, fixed diameter and had difficulty migrating the hot combustion products at the OD radially inward across an axial core flow to present a uniform temperature distribution to the first turbine stage. This study draws from preliminary computational analysis which enabled experimental testing of a new UCC configuration that featured a smaller diameter circumferential cavity that exhausted axially into a dilution zone positioned just upstream of the nozzle guide vanes. The combustor was sized as a replacement burner for the JetCat P90 RXi small-scale turbine engine and fit inside the engine casing. This combustor configuration achieved a 33% length reduction compared to the stock JetCat combustor and achieved comparable engine performance across a limited operating range. Self-sustained engine operation was achieved with a rotating compressor and turbine making this study the first to achieve operation of a UCC-powered turbine engine.

scholarly journals Nytrox as “Drop-in” Replacement for Gaseous Oxygen in SmallSat Hybrid Propulsion Systems

Aerospace ◽  
2020 ◽  
Vol 7 (4) ◽  
pp. 43 ◽  
Author(s):  
Stephen A. Whitmore
Keyword(s):  
Specific Impulse ◽  
Acrylonitrile Butadiene Styrene ◽  
N2o Decomposition ◽  
Combustion Efficiency ◽  
Future Research ◽  
Propulsion Systems ◽  
Gaseous Oxygen ◽  
Thrust Coefficient ◽  
Hybrid Propulsion ◽  
Dissolved Carbon

A medical grade nitrous oxide (N2O) and gaseous oxygen (GOX) “Nytrox” blend is investigated as a volumetrically-efficient replacement for GOX in SmallSat-scale hybrid propulsion systems. Combined with 3-D printed acrylonitrile butadiene styrene (ABS), the propellants represent a significantly safer, but superior performing, alternative to environmentally-unsustainable spacecraft propellants like hydrazine. In a manner analogous to the creation of soda-water using dissolved carbon dioxide, Nytrox is created by bubbling GOX under pressure into N2O until the solution reaches saturation. Oxygen in the ullage dilutes N2O vapor and increases the required decomposition energy barrier by several orders of magnitude. Thus, risks associated with inadvertent thermal or catalytic N2O decomposition are virtually eliminated. Preliminary results of a test-and-evaluation campaign are reported. A small spacecraft thruster is first tested using gaseous oxygen and 3-D printed ABS as the baseline propellants. Tests were then repeated using Nytrox as a “drop-in” replacement for GOX. Parameters compared include ignition reliability, latency, initiation energy, thrust coefficient, characteristic velocity, specific impulse, combustion efficiency, and fuel regression rate. Tests demonstrate Nytrox as an effective replacement for GOX, exhibiting a slightly reduced specific impulse, but with significantly higher volumetric efficiency. Vacuum specific impulse exceeding 300 s is reported. Future research topics are recommended.

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