Hybrid Rocket(Volume II)

A special issue of Aerospace (ISSN 2226-4310).

Deadline for manuscript submissions: closed (15 September 2021) | Viewed by 46615

Special Issue Editors


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Guest Editor
Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara City 252-5210, Kanagawa, Japan
Interests: aerospace propulsion

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Guest Editor
Department of Mechanical Engineering, Koc University, Istanbul, Turkey
Interests: rocket propulsion

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Guest Editor
Dipartimento Ingn Ind, Università di Napoli "Federico II", I-80125 Naples, Italy
Interests: chemical propulsion; fluid dynamics
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Special Issue Information

Dear Colleagues,

If you are asked what the biggest barriers to future space transportation development are, what do you list?

The fact is, whereas airframe loss rates are in the order of one per 10 million, space flights have remained high, in the order of one per cent during the past 40 years. The system safety and reliability of space transportation have been improved by enhancing system redundancy, reducing the failure rate of onboard equipment, and strict quality control. However, these statistics imply that these methods are already at their limit. It is essential for space transportation to acquire drastic resilience against hazards in order to demonstrate safety and reliability comparable with those of air transportation. I hope to develop a hybrid rocket that can be an essentially non-explosive propulsion system, as a means to improve the resilience of space transportation in the future.

Aerospace’s Special Issue “Advances in Hybrid Rocket Technology and Related Analysis Methodologies” was edited by Dr. Carmine Carmicino, in which fourteen open-access papers (10 articles, three reviews and one editorial) were published between 6 March 2019 and 13 May 2020. This resulted in the publication of the latest technical articles and informative technical reviews from all aspects of hybrid rockets. I think this second edition will be of great value as it follows the previous one in continuously updating the technical information and further extends itself to new technical fields. Here, I would like to welcome Dr. Arif Karabeyoglu and Dr. Carmine Carmicino as co-editors to organize the contents of this edition and ensure that they are broader and more attractive.

Soon, the hybrid rocket engine from Virgin Galactic SpaceShipTwo will be put to practical use in space travel. There is no doubt that the technology of hybrid rockets will be improved with the aim of safer manned space flights. This means that investment in technological research will or shall occur. This edition deals, as well as with advances in hybrid rocket technology and related analysis methodologies dealt with previously, with novel space transportation systems, mission concepts and optimization using hybrid rockets. I would also welcome articles that deal with how we can deepen the involvement of hybrid rockets, as well as technical papers dealing with other aspects of hybrid rockets, such as CFD, internal ballistics, combustion instabilities, propellant performance. Additonally, since quite a bit of activity on hybrid flight systems around the world is going on, so topics on such systems and more practical aspects of hybrid rocket based systems can be also included.

Prof. Dr. Toru Shimada
Dr. Arif Karabeyoglu
Dr. Carmine Carmicino
Guest Editors

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Published Papers (12 papers)

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Editorial

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4 pages, 177 KiB  
Editorial
Special Issue “Hybrid Rocket (Volume II)”
by Toru Shimada, Carmine Carmicino and Arif Karabeyoglu
Aerospace 2022, 9(5), 233; https://doi.org/10.3390/aerospace9050233 - 24 Apr 2022
Cited by 3 | Viewed by 1880
Abstract
Over the past 40 years, the loss rate for commercial passenger aircrafts has decreased down to about one in ten million, whereas the loss rate for spaceflight has remained high, in the 1% range [...] Full article
(This article belongs to the Special Issue Hybrid Rocket(Volume II))

Research

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9 pages, 4248 KiB  
Article
Large-Scale CAMUI Type Hybrid Rocket Motor Scaling, Modeling, and Test Results
by Tor Viscor, Landon Kamps, Kazuo Yonekura, Hikaru Isochi and Harunori Nagata
Aerospace 2022, 9(1), 1; https://doi.org/10.3390/aerospace9010001 - 21 Dec 2021
Cited by 11 | Viewed by 3291
Abstract
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 [...] Read more.
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. Full article
(This article belongs to the Special Issue Hybrid Rocket(Volume II))
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13 pages, 3257 KiB  
Article
Burn Time Correction of Start-Up Transients for CAMUI Type Hybrid Rocket Engine
by Tor Viscor, Hikaru Isochi, Naoto Adachi and Harunori Nagata
Aerospace 2021, 8(12), 385; https://doi.org/10.3390/aerospace8120385 - 09 Dec 2021
Cited by 2 | Viewed by 2315
Abstract
Burn time errors caused by various start-up transient effects have a significant influence on the regression modelling of hybrid rockets. Their influence is especially pronounced in the simulation model of the Cascaded Multi Impinging Jet (CAMUI) hybrid rocket engine. This paper analyses these [...] Read more.
Burn time errors caused by various start-up transient effects have a significant influence on the regression modelling of hybrid rockets. Their influence is especially pronounced in the simulation model of the Cascaded Multi Impinging Jet (CAMUI) hybrid rocket engine. This paper analyses these transient burn time errors and their effect on the regression simulations for short burn time engines. To address these errors, the equivalent burn time is introduced and is defined as the time the engine would burn if it were burning at its steady-state level throughout the burn time to achieve the measured total impulse. The accuracy of the regression simulation with and without the use of equivalent burn time is then finally compared. Equivalent burn time is shown to address the burn time issue successfully for port regression and, therefore, also for other types of cylindrical port hybrid rocket engines. For the CAMUI-specific impinging jet fore-end and back-end surfaces, though, the results are inconclusive. Full article
(This article belongs to the Special Issue Hybrid Rocket(Volume II))
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14 pages, 6053 KiB  
Article
Experimental Study on the Mass Flow Rate of the Self-Pressurizing Propellants in the Rocket Injector
by Tomasz Palacz and Jacek Cieślik
Aerospace 2021, 8(11), 317; https://doi.org/10.3390/aerospace8110317 - 26 Oct 2021
Cited by 2 | Viewed by 2980
Abstract
High vapor pressure propellants such as nitrous oxide are widely used in experimental hybrid and liquid rockets as they can be used in a self-pressurization mode, eliminating the need for external pressurization or pumps and simplifying the design of the rocket system. This [...] Read more.
High vapor pressure propellants such as nitrous oxide are widely used in experimental hybrid and liquid rockets as they can be used in a self-pressurization mode, eliminating the need for external pressurization or pumps and simplifying the design of the rocket system. This approach causes the two-phase flow in the feed system and the injector orifices, which cannot be easily modeled and accounted for in the design. A dedicated test stand has been developed to better understand how the two-phase flow of the self-pressurizing propellant impacts the mass flow characteristics, enabling the simulation of the operating conditions in the rocket engine. The injectors have been studied in the range of ΔP. The flow regimes have been identified, which can be predicted by the SPI and HEM models. It has been shown that the two-phase flow quality upstream of the injector may impact the discharge coefficient in the SPI region and the accuracy of the HEM model. It has been found that the transition to the critical flow region depends on the L/D ratio of the injector orifice. A series of conclusions can be drawn from this work to design the rocket injector with a self-pressurizing propellant to better predict the mass flow rate and ensure stable combustion. Full article
(This article belongs to the Special Issue Hybrid Rocket(Volume II))
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27 pages, 10475 KiB  
Article
Hybrid Rockets as Post-Boost Stages and Kick Motors
by Landon Kamps, Shota Hirai and Harunori Nagata
Aerospace 2021, 8(9), 253; https://doi.org/10.3390/aerospace8090253 - 07 Sep 2021
Cited by 19 | Viewed by 3434
Abstract
Hybrid rockets are attractive as post-boost stages and kick motors due to their inherent safety and low cost, but it is not clear from previous research which oxidizer is most suitable for maximizing ΔV within a fixed envelope size, or what impact O [...] Read more.
Hybrid rockets are attractive as post-boost stages and kick motors due to their inherent safety and low cost, but it is not clear from previous research which oxidizer is most suitable for maximizing ΔV within a fixed envelope size, or what impact O/F shift and nozzle erosion will have on ΔV. A standard hybrid rocket design is proposed and used to clarify the impact of component masses on ΔV within three 1 m3 envelopes of varying height-to-base ratios. Theoretical maximum ΔV are evaluated first, assuming constant O/F and no nozzle erosion. Of the four common liquid oxidizers: H2O2 85 wt%, N2O, N2O4, and LOX, H2O2 85 wt% is shown to result in the highest ΔV, and N2O is shown to result in the highest density ΔV, which is the ΔV normalized for motor density. When O/F shift is considered, the ΔV decreases by 9% for the N2O motor and 12% for the H2O2 85 wt% motor. When nozzle erosion is also considered, the ΔV decreases by another 7% for the H2O2 85 wt% motor and 4% for the N2O motor. Even with O/F shift and nozzle erosion, the H2O2 85 wt% motor can accelerate itself (916 kg) upwards of 4000 m/s, and the N2O motor (456 kg) 3550 m/s. Full article
(This article belongs to the Special Issue Hybrid Rocket(Volume II))
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15 pages, 900 KiB  
Article
Numerical Simulations of the Internal Ballistics of Paraffin–Oxygen Hybrid Rockets at Different Scales
by Mario Tindaro Migliorino, Daniele Bianchi and Francesco Nasuti
Aerospace 2021, 8(8), 213; https://doi.org/10.3390/aerospace8080213 - 05 Aug 2021
Cited by 10 | Viewed by 2066
Abstract
Hybrid rockets are considered a promising future propulsion alternative for specific applications to solid or liquid rockets. In order to raise their technology readiness level, it is important to perform predictive numerical simulations of their internal ballistics. The objective of this work is [...] Read more.
Hybrid rockets are considered a promising future propulsion alternative for specific applications to solid or liquid rockets. In order to raise their technology readiness level, it is important to perform predictive numerical simulations of their internal ballistics. The objective of this work is to describe and validate a numerical approach based on Reynolds-averaged Navier–Stokes simulations with sub-models for fluid–surface interaction, radiation, chemistry, and turbulence. Particular attention is given to scale effects by considering two different paraffin–oxygen hybrid rocket engines and a simplified grain evolution approach from the initial to the final port diameter. Moreover, a mild sensitivity of the computed regression rate to paraffin’s melting temperature, surface radiation emissivity, and Schmidt numbers is observed. Results highlight the increasing importance of radiation effects at larger scales and pressures. A numerical rebuilding of regression rate and pressure is obtained with simulations at the time-space-averaged port diameter, producing a reasonable agreement with the available experimental data, but a noticeable improvement is obtained by considering the grain evolution in time. Full article
(This article belongs to the Special Issue Hybrid Rocket(Volume II))
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14 pages, 3254 KiB  
Article
Passive Control of Low-Frequency Instability in Hybrid Rocket Combustion
by Wonjeong Hyun, Jina Kim, Heesang Chae and Changjin Lee
Aerospace 2021, 8(8), 204; https://doi.org/10.3390/aerospace8080204 - 28 Jul 2021
Cited by 8 | Viewed by 1959
Abstract
The occurrence of low-frequency instability (LFI) appears to be related to multiple interactions among many complex physical processes, such as vortex shedding, boundary-layer oscillation, and additional combustion in the post-combustion chamber. In this study, two combustion tests were conducted to suppress LFI and [...] Read more.
The occurrence of low-frequency instability (LFI) appears to be related to multiple interactions among many complex physical processes, such as vortex shedding, boundary-layer oscillation, and additional combustion in the post-combustion chamber. In this study, two combustion tests were conducted to suppress LFI and to examine which physical processes its occurrence was most sensitive. In the first test, two fuel inserts were used to modify the formation of a boundary layer, vortex shedding at the end of the fuel, and vortex impingement. In the second test, the fuel insert located at the front end was replaced with swirl injection. The first test was aimed at controlling and suppressing the initiation of LFI using fuel inserts, through which a small step appeared gradually due to differences in the regression rates of the two materials, i.e., polymethyl methacrylate and high-density polyethylene. The test results confirmed that (i) there are physical connections among several processes, such as the thermoacoustic coupling between p′and q′ and the oscillations of the upstream boundary flow, and (ii) LFI suppression is possible by disrupting or eliminating the connections among these physical processes. The second test was also aimed to control LFI while minimizing the deviation in combustion performance using proper swirl injection along with a fuel insert. Even when replaced by swirl injection, LFI suppression was still possible and showed reasonable combustion performance without causing too much deviation from the baseline in terms of the oxygen-to-fuel ratio and the fuel regression rate. Full article
(This article belongs to the Special Issue Hybrid Rocket(Volume II))
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14 pages, 372 KiB  
Article
Optimal Design of Electrically Fed Hybrid Mars Ascent Vehicle
by Lorenzo Casalino, Filippo Masseni and Dario Pastrone
Aerospace 2021, 8(7), 181; https://doi.org/10.3390/aerospace8070181 - 06 Jul 2021
Cited by 12 | Viewed by 2426
Abstract
The optimal design of the propulsion system for a potential Mars Ascent Vehicle is analyzed, in the context of the Mars Sample Return Mission. The Mars Ascent Vehicle has to perform an initial ascent phase from the surface and then circularize into a [...] Read more.
The optimal design of the propulsion system for a potential Mars Ascent Vehicle is analyzed, in the context of the Mars Sample Return Mission. The Mars Ascent Vehicle has to perform an initial ascent phase from the surface and then circularize into a 170 km orbit. A two-stage launcher is taken into account: the same hybrid rocket engine is considered for both stages in order to limit the development costs. A cluster of two, three or four engines is employed in the first stage, whereas a single engine is always used in the second stage. Concerning the feeding system, three alternatives are taken into consideration, namely a blow down, a regulated and an electric turbo-pump feed system. The latter employs an electric motor to drive the oxidizer turbopump, whereas the power is supplied to the motor by lithium batteries. All the design options resulted in viable Mars Ascent Vehicle configurations (payloads are in the range of 70–100 kg), making the hybrid alternative worth considering for the sample return mission. The use of an electric turbo-pump feed system determines the highest vehicle performance with an estimated 10–25% payload gain with respect to gas-pressure feed systems. Full article
(This article belongs to the Special Issue Hybrid Rocket(Volume II))
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Review

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23 pages, 24094 KiB  
Review
Development of Green Storable Hybrid Rocket Propulsion Technology Using 98% Hydrogen Peroxide as Oxidizer
by Adam Okninski, Pawel Surmacz, Bartosz Bartkowiak, Tobiasz Mayer, Kamil Sobczak, Michal Pakosz, Damian Kaniewski, Jan Matyszewski, Grzegorz Rarata and Piotr Wolanski
Aerospace 2021, 8(9), 234; https://doi.org/10.3390/aerospace8090234 - 24 Aug 2021
Cited by 26 | Viewed by 8996
Abstract
This paper presents the development of indigenous hybrid rocket technology, using 98% hydrogen peroxide as an oxidizer. Consecutive steps are presented, which started with interest in hydrogen peroxide and the development of technology to obtain High Test Peroxide, finally allowing concentrations of up [...] Read more.
This paper presents the development of indigenous hybrid rocket technology, using 98% hydrogen peroxide as an oxidizer. Consecutive steps are presented, which started with interest in hydrogen peroxide and the development of technology to obtain High Test Peroxide, finally allowing concentrations of up to 99.99% to be obtained in-house. Hydrogen peroxide of 98% concentration (mass-wise) was selected as the workhorse for further space propulsion and space transportation developments. Over the course nearly 10 years of the technology’s evolution, the Lukasiewicz Research Network—Institute of Aviation completed hundreds of subscale hybrid rocket motor and component tests. In 2017, the Institute presented the first vehicle in the world to have demonstrated in-flight utilization for 98% hydrogen peroxide. This was achieved by the ILR-33 AMBER suborbital rocket, which utilizes a hybrid rocket propulsion as the main stage. Since then, three successful consecutive flights of the vehicle have been performed, and flights to the Von Karman Line are planned. The hybrid rocket technology developments are described. Advances in hybrid fuel technology are shown, including the testing of fuel grains. Theoretical studies and sizing of hybrid propulsion systems for spacecraft, sounding rockets and small launch vehicles have been performed, and planned further developments are discussed. Full article
(This article belongs to the Special Issue Hybrid Rocket(Volume II))
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41 pages, 1612 KiB  
Review
Hybrid Rocket Engine Design Optimization at Politecnico di Torino: A Review
by Lorenzo Casalino, Filippo Masseni and Dario Pastrone
Aerospace 2021, 8(8), 226; https://doi.org/10.3390/aerospace8080226 - 13 Aug 2021
Cited by 13 | Viewed by 4305
Abstract
Optimization of Hybrid Rocket Engines at Politecnico di Torino began in the 1990s. A comprehensive review of the related research activities carried out in the last three decades is here presented. After a brief introduction that retraces driving motivations and the most significant [...] Read more.
Optimization of Hybrid Rocket Engines at Politecnico di Torino began in the 1990s. A comprehensive review of the related research activities carried out in the last three decades is here presented. After a brief introduction that retraces driving motivations and the most significant steps of the research path, the more relevant aspects of analysis, modeling and achieved results are illustrated. First, criteria for the propulsion system preliminary design choices (namely the propellant combination, the feed system and the grain design) are summarized and the engine modeling is presented. Then, the authors describe the in-house tools that have been developed and used for coupled trajectory and propulsion system design optimization. Both deterministic and robust-based approaches are presented. The applications that the authors analyzed over the years, starting from simpler hybrid powered sounding rocket to more complex multi-stage launchers, are then presented. Finally, authors’ conclusive remarks on the work done and their future perspective in the context of the optimization of hybrid rocket propulsion systems are reported. Full article
(This article belongs to the Special Issue Hybrid Rocket(Volume II))
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19 pages, 2599 KiB  
Review
Challenges of Ablatively Cooled Hybrid Rockets for Satellites or Upper Stages
by Francesco Barato
Aerospace 2021, 8(7), 190; https://doi.org/10.3390/aerospace8070190 - 14 Jul 2021
Cited by 7 | Viewed by 3408
Abstract
Ablative-cooled hybrid rockets could potentially combine a similar versatility of a liquid propulsion system with a much simplified architecture. These characteristics make this kind of propulsion attractive, among others, for applications such as satellites and upper stages. In this paper, the use of [...] Read more.
Ablative-cooled hybrid rockets could potentially combine a similar versatility of a liquid propulsion system with a much simplified architecture. These characteristics make this kind of propulsion attractive, among others, for applications such as satellites and upper stages. In this paper, the use of hybrid rockets for those situations is reviewed. It is shown that, for a competitive implementation, several challenges need to be addressed, which are not the general ones often discussed in the hybrid literature. In particular, the optimal thrust to burning time ratio, which is often relatively low in liquid engines, has a deep impact on the grain geometry, that, in turn, must comply some constrains. The regression rate sometime needs to be tailored in order to avoid unreasonable grain shapes, with the consequence that the dimensional trends start to follow some sort of counter-intuitive behavior. The length to diameter ratio of the hybrid combustion chamber imposes some packaging issues in order to compact the whole propulsion system. Finally, the heat soak-back during long off phases between multiple burns could compromise the integrity of the case and of the solid fuel. Therefore, if the advantages of hybrid propulsion are to be exploited, the aspects mentioned in this paper shall be carefully considered and properly faced. Full article
(This article belongs to the Special Issue Hybrid Rocket(Volume II))
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Other

16 pages, 8727 KiB  
Technical Note
Design, Production and Evaluation of 3D-Printed Mold Geometries for a Hybrid Rocket Engine
by Benedict Grefen, Johannes Becker, Stefan Linke and Enrico Stoll
Aerospace 2021, 8(8), 220; https://doi.org/10.3390/aerospace8080220 - 08 Aug 2021
Cited by 9 | Viewed by 3803
Abstract
The feasibility of 3D-printed molds for complex solid fuel block geometries of hybrid rocket engines is investigated. Additively produced molds offer more degrees of freedom in designing an optimized but easy to manufacture mold. The solid fuel used for this demonstration was hydroxyl-terminated [...] Read more.
The feasibility of 3D-printed molds for complex solid fuel block geometries of hybrid rocket engines is investigated. Additively produced molds offer more degrees of freedom in designing an optimized but easy to manufacture mold. The solid fuel used for this demonstration was hydroxyl-terminated polybutadiene (HTPB). Polyvinyl alcohol (PVA) was chosen as the mold material due to its good dissolving characteristics. It is shown that conventional and complex geometries can be produced reliably with the presented methods. In addition to the manufacturing process, this article presents several engine tests with different fuel grain geometries, including a short overview of the test bed, the engine and first tests. Full article
(This article belongs to the Special Issue Hybrid Rocket(Volume II))
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