This is the 3rd review of papers from the 46th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit (JPC) which took place from 25th to 28th of July 2010, in Nashville, TN.
There were far more papers on analytical and computational studies relating to detonations and detonation engines, than papers on experimental studies of the same.
There were 3 papers from the University of Texas at Arlington, with 2 being on Rotating Detonation Engines (RDEs). The two RDE papers were reports of analytical studies of RDE models.
AIAA 2010-7039 “Airbreathing Rotating Detonation Wave Engine Cycle Analysis” claims that RDEs are not very efficient at low supersonic speeds but have reasonable or satisfactory performance at Mach 5.
In the paper AIAA 2010-7040 “Detonation Engine Performance Comparison Using First and Second Law Analyses”, a comparative s study was done of an RDE and a PDE. The results show that a PDE is more efficient at low supersonic speeds, but the relative RDE performance gradually increases until it becomes comparable close to Mach 5.
AIAA 2010-6767 “Proof-of-Principle Detonation Driven, Linear Electric Generator Facility” was an interesting paper, the result of a collaborative study by UT Arlington and Neo Power Technology, Norway. They tested a prototype PDE driven linear electric generator. The regular method of extracting power from a jet or rocket engine is to use a turbine to convert the kinetic energy of the working fluid to rotating shaft power. In this method, a PDE’s power is converted into linear oscillating motion which is then captured by a linear electric generator into ac electric power. Various fuels such as hydrogen, methane and propane were tested in the engine.
Another paper on the computational analysis of RDE was AIAA 2010-6880 “Numerical Investigation of Rotating Detonation Engines.” The author claims that the study revealed that the specific impulse of the RDE model was dependent on pressure ratio (outlet/inlet), whereas the mass flow and propulsive force were primarily dependent on the stagnation properties of the inlet micro-nozzles. The specific impulse varied from 3845 to 5560 seconds over a pressure ratio of 5 to 30.
As usual, there were several detonation engine based papers from General Electric. This time, the papers were all on analytical studies. AIAA 2010-6714 was entitled “Limit Cycle Investigations of Pulse Detonation Combustor for Pulse Detonation Turbine Engine” and AIAA 2010-6715 was entitled “Estimation of PDE Performance Using a Pulsed Limit Cycle Unsteady Combustion Calculation.”
AIAA 2010-6716 entitled “A Lumped Volume Model for the Performance of a Pulse Detonation Combustor” was withdrawn.
A paper on computational modeling from a researcher at NASA Glen Research Center in Cleveland, Ohio, is AIAA 2010-6717 “A Simplified Model for Detonation Based Pressure-Gain Combustors.”
AIAA 2010-6882 “Experimental Studies of the Unsteady Ejector Mode of a Pulse Detonation Rocket-Based Combined Cycle Engine” is a paper from Penn State. A brief excerpt from the abstract is given here.
The results of an experimental investigation of the unsteady ejector mode of a pulse detonation rocket (PDR)-based combined cycle engine are presented in this paper, to determine the PDR’s viability as a suitable candidate for the ejector mode of a combined cycle engine for space propulsion. These experimental efforts at The Pennsylvania State University complement concurrent NASA computational studies that have predicted that the PDR-based combined cycle engine configuration has better performance than a conventional rocket-based combined cycle engine. A high frequency, gaseous H2-O2 PDR engine was integrated into the flowpath of a modular 2-D rocket-based combined cycle duct for use as an unsteady ejector. Static thrust measurements were then acquired for hot fire experiments for fill pressures in excess of 20 atm for both the baseline PDR engine and the PDR-based combined cycle engine. Positive thrust augmentation was observed for the PDR-based combined cycle engine at four different operating frequencies, including a 46% augmentation at 80 Hz. However, augmentation suffered at operating frequencies above the optimal condition due to incomplete propellant filling from shorter cycle timing. Further experiments investigated the effects of variances in geometric and system parameters such as secondary air flow rate, downstream secondary hydrogen injection, and nozzle ratio on static thrust.
There were 3 papers on wave rotors from the same source, Indiana University-Purdue University at Indianapolis (IUPUI) and Purdue University. Two of the papers were computational modeling of wave rotors, namely AIAA 2010-7041 “Wave Rotor Combustor Aerothermodynamic Design and Model Validation based on Initial Testing” and AIAA 2010-7042 “Mixing and Ignition Potential of a Transient Confined Turbulent Jet in a Wave-Rotor Constant-Volume Combustor “.
The third paper AIAA 2010-7043 “Experimental Investigation on the Wave Rotor Constant Volume Combustor” was as the name suggests a report on the experimental test of a wave rotor.
The abstract reads as follows.
A wave rotor constant volume combustor was designed and built as a collaborative work of Rolls-Royce, Indiana University-Purdue University Indianapolis (IUPUI), and Purdue University. The experiment was designed to operate at rotational speeds of up to 4,200 rpm with air mass flow rates of approximately 18 lbm per second. Initial tests were conducted at 2,100 rpm with ethylene as fuel. The rig was operated with different fuel injection schemes to investigate operational characteristics of the combustor. Successful combustion and pressure gain were achieved over a range of operating conditions.
More information on wave rotor can be found here.
- Wave Rotor Research Program at Michigan State University: Research website, Paper AIAA 2005-3844, Paper IMECE 2004-60082 A Review of Wave Rotor Technology and Its Applications.
- Wikipedia article on a type of wave rotor used in automobiles called “Pressure Wave Supercharger“
- An article explaining the Comprex wave rotor supercharger.
- Paper on Wave Rotors by researchers from MSU and IUPUI: A Review of Wave Rotor Technology and Its Applications.