scholarly journals Green gelled propellant highly throtteable rocket motor and gas generator technology: status and application

2019 ◽  
Author(s):  
P. Caldas Pinto ◽  
H.K. Ciezki ◽  
K.W. Naumann ◽  
J. Ramsel ◽  
P. Kröger ◽  
...  
Keyword(s):  
Motor Development ◽  
Basic Research ◽  
Rocket Motor ◽  
Effective Control ◽  
Gas Generator ◽  
Component Level ◽  
Functional Aspects ◽  
Gelled Propellant ◽  
Ignition And Combustion ◽  
Gelled Propellants

Work on gel propulsion began in Germany in 1999. The German Gel Propulsion Technology (GGPT) Program started in 2001 from a white sheet of paper, proposed by the DLR Institute of Space Propulsion, Bayern-Chemie (BC), and the Fraunhofer Institute of Chemical Technology. Aim of the first phase was to develop the technology needed to build a rocket motor burning gelled propellants and to demonstrate its operability by a free flight within significantly less than a decade. The research and development activities were guided by a suitable principal concept for a gelled propellant rocket motor (GRM). Based on theoretical considerations (regarding functional aspects) and experimental pre-tests (propellant development, gelation, rheology, spraying, ignition, and combustion), a motor concept was pre-selected and the motor developed. The identified requirements were proven in December 2009 by two successful demonstration flights. The achieved know-how from basic research and technology (R+T) development has been consolidated in an application-oriented way on component level up to motor development. Within this scope, also, the goal of an effective control of the thrust by throttling the propellant mass flow rate (PMFR) while maintaining an optimum combustion chamber (CC) pressure could be achieved. This publication describes briefly several major advances in the development of the gel propulsion technology in Germany from rheology to combustor development to the thrust and pressure controller of a GRM.

Modeling the Effects of Variable Intake Valve Timing on Diesel HCCI Combustion at Varying Load, Speed, and Boost Pressures

2008 ◽  
Vol 130 (5) ◽  
Author(s):  
C. L. Genzale ◽  
S.-C. Kong ◽  
R. D. Reitz
Keyword(s):  
Operating Conditions ◽  
Effective Control ◽  
Intake Valve ◽  
Valve Timing ◽  
Detailed Chemical Kinetics ◽  
Hcci Combustion ◽  
Wide Range ◽  
Particulate Matter Emissions ◽  
Charge Mixture ◽  
Ignition And Combustion

Homogeneous charge compression ignition (HCCI) operated engines have the potential to provide the efficiency of a typical diesel engine, with very low NOx and particulate matter emissions. However, one of the main challenges with this type of operation in diesel engines is that it can be difficult to control the combustion phasing, especially at high loads. In diesel HCCI engines, the premixed fuel-air charge tends to ignite well before top dead center, especially as load is increased, and a method of delaying the ignition is necessary. The development of variable valve timing (VVT) technology may offer an important advantage in the ability to control diesel HCCI combustion. VVT technology can allow for late intake valve closure (IVC) times, effectively changing the compression ratio of the engine. This can decrease compression temperatures and delay ignition, thus allowing the possibility to employ HCCI operation at higher loads. Furthermore, fully flexible valve trains may offer the potential for dynamic combustion phasing control over a wide range of operating conditions. A multidimensional computational fluid dynamics model is used to evaluate combustion event phasing as both IVC times and operating conditions are varied. The use of detailed chemical kinetics, based on a reduced n-heptane mechanism, provides ignition and combustion predictions and includes low-temperature chemistry. The use of IVC delay is demonstrated to offer effective control of diesel HCCI combustion phasing over varying loads, engine speeds, and boost pressures. Additionally, as fueling levels are increased, charge mixture properties are observed to have a significant effect on combustion phasing. While increased fueling rates are generally seen to advance combustion phasing, the reduction of specific heat ratio in higher equivalence ratio mixtures can also cause noticeably slower temperature rise rates, affecting ignition timing and combustion phasing. Variable intake valve timing may offer a promising and flexible control mechanism for the phasing of diesel HCCI combustion. Over a large range of boost pressures, loads, and engine speeds, the use of delayed IVC is shown to sufficiently delay combustion in order to obtain optimal combustion phasing and increased work output, thus pointing towards the possibility of expanding the current HCCI operating range into higher load points.

Design of a Solid Propellant Air Turbo Rocket for a Tactical Air-Launched Missile

2007 ◽  
Author(s):  
Fredrik Haglind ◽  
Henrik Edefur ◽  
Stefan Olsson
Keyword(s):  
Solid Propellant ◽  
Combined Cycle ◽  
Rocket Motor ◽  
Solid Rocket Motor ◽  
Gas Generator ◽  
Number Range ◽  
Solid Propellant Rocket ◽  
Solid Rocket ◽  
Novel Concept ◽  
Propellant Rocket

Traditionally, air-launched missiles are powered by a turbojet engine, rocket motor or a ramjet engine. A novel concept that may offer advantages over these concepts is the Air Turbo Rocket (ATR), which is a combined cycle engine, featuring a cycle where the turbine is isolated from the core engine flow entirely and powered by a separate gas generator. This paper is aimed at assessing the suitability of the solid propellant ATR as power source for a tactical air-launched missile. The ATR cycle is designed to achieve optimum performance, and a suitable solid propellant is selected. In addition, a turbojet and a solid rocket motor are designed for the same requirements, and the performances of these three engine concepts are compared. The ATR offers high thrust to weight and thrust to frontal area weight ratios, throttleability, and a wide speed-altitude operating envelope. The calculations suggest that, provided that the afterburning cooling issues can be solved, it would be reasonable to design the ATR such that a stoichiometric fuel/air mixture is obtained in the afterburner. For the Mach number range evaluated here, the ATR may offer advantages over the turbojet and the solid propellant rocket motor.

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