Scott Meyer

Facility Development for Testing of Wave Rotor Combustion Rig

A Wave Rotor Combustion Rig (WRCR) is under development by a team including Purdue University, Rolls-Royce (LibertyWorks

Variable Thrust, Multiple Start Hybrid Motor Solutions for Missile and Space Applications

Energy management in missile systems can provide substantial performance advantages, especially for modern missiles capable of all-aspect engagements. Energy management in upper stage propulsion systems allows for the same propulsion system to be used for a variety of payloads and orbits. The objectives of the study were to assess throttling capabilities and novel fuel concepts for hybrid motors. Experimental studies were conducted using 90% hydrogen peroxide (HP) with a variety of unique fuels in both direct injection and catalytic bed injection approaches. Performance efficiencies ranged from 91% to 100% and the combustion in all tests was smooth with the highest level of combustion roughness reaching only 0.6% of the steady state pressure. These hybrid motor tests also displayed the expected connection between the oxidizer flux level and the time required to ignite the fuel grain with higher flux levels resulting in lower ignition delays. Substantial throttling capabilities were demonstrated. Throttle-down tests analogous to a powered vertical landing exhibited a 10:1 throttling ratio with stable combustion across the entire range. Boost/Sustain/Boost thrust profiles representative of tactical solid rocket motors were tested with 75%, 50%, and lower sustain-to-boost chamber pressure ratios with rapid throttle-up achieved following the sustain period. To add multiple-start capability to a hybrid motor without reliance on a catalyst bed or separate ignition system, fuel grains catalytic with the oxidizer were investigated. Test fires of these fuel grains in the hybrid motor test article exhibited regression rates 2.5 times higher than the highest regression rates realized with the uncatalyzed polyethylene fuel grains.

Dual-pump coherent anti-Stokes Raman scattering system for temperature and species measurements in an optically accessible high-pressure gas turbine combustor facility

The development and implementation of a dual-pump coherent anti-Stokes Raman scattering (DP-CARS) system employing two optical sub-systems to measure temperature and major species concentrations at multiple locations in the flame zone of a high-pressure, liquid-fueled gas turbine combustor are discussed. An optically accessible gas turbine combustor facility (GTCF) was utilized to perform these experiments. A window assembly has been designed, fabricated, and assembled in the GTCF to allow optical access from three directions using a pair of thin and thick fused silica windows on each side. A lean direct injection (LDI) device consisting of an array of nine integrated air swirlers and fuel injectors was operated using Jet-A fuel at inlet air temperatures up to 725 K and combustor pressures up to 1.03 MPa. The DP-CARS system was used to measure temperature and CO2/N2 concentration ratio on single laser shots. An injection-seeded optical parametric oscillator (OPO) was used as a narrowband pump laser source in order to potentially reduce shot-to-shot fluctuations in the CARS data. Large prisms mounted on computer-controlled translation stages were used to direct the CARS beams either into the main leg optical system for measurements in the GTCF or to a reference leg optical system for measurements of the non-resonant spectrum and for alignment of the CARS system. The spatial maps of temperature and major species concentrations were obtained in high-pressure LDI flames by translating the CARS probe volume in the axial and vertical directions inside the combustor rig without loss of optical alignment.

CORDIERITE-BASED CATALYTIC BEDS FOR 98% HYDROGEN PEROXIDE

A new type of catalyst system for use in decomposing hydrogen peroxide was studied. The catalyst system was composed of sodium permanganate loaded onto a cordierite-based ceramic material that had not previously been used in this manner. Both immersion tests and full engine flow tests were conducted for a variety of configurations and preparation procedures. One type of catalyst bed had good performance, at approximately 94% C* efficiency. The performance of the other catalyst beds was between 40% and 70%. Nomenclature

The development of an optically accessible, high-power combustion test rig.

This work summarizes the development of a gas turbine combustion experiment which will allow advanced optical measurements to be made at realistic engine conditions. Facility requirements are addressed, including instrumentation and control needs for remote operation when working with high energy flows. The methodology employed in the design of the optically accessible combustion chamber is elucidated, including window considerations and thermal management of the experimental hardware under extremely high heat loads. Experimental uncertainties are also quantified. The stable operation of the experiment is validated using multiple techniques and the boundary conditions are verified. The successful prediction of operating conditions by the design analysis is documented and preliminary data are shown to demonstrate the capability of the experiment to produce high-fidelity datasets for advanced combustion research.

Experimental Investigation on the Wave Rotor Constant Volume Combustor

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.

Effect of Aviation Fuel Type and Fuel Injection Conditions on Non-reacting Spray Characteristics of a Hybrid Airblast Fuel Injector

I njector spray characteristics have a significant influence on the combustion performance in a gas turbine engine, including an impact on dynamics, emissions and component life. Furthermore, commercial aviation faces fuel cost, environmental, and energy security challenges that arise from the use of petroleum based jet fuels. Sustainable alternative jet fuels can help address these challenges and need to be characterized in their spray performance. The present work describes the detailed characterization of several alternative fuels using a hybrid airblast atomizer on the basis of spray shape, droplet size and velocity distribution at a range of operating conditions including fuel temperature, injector pressure drop and spray chamber pressure and temperature. The characterization is done using optical patternation, phase Doppler anemometry (dual-PDPA) and high speed back-lit imaging. The measurements obtained as part of this work provide the validation data-set for computational modeling of the spray behavior which forms a critical part of the broader project. The results show a strong influence of the fuel temperature on the spray, with lower temperature (290 K to 240 K) decreasing the atomization quality by 14%, while the effect of fuel injection pressure on the spray is minimal. A large effect of pressure drop across the injector is seen on the spray, with a change from 2% to 6% leading to a decrease in drop size of up to 36%, which can result of a shift in the secondary breakup regime of the spray.

Pressure Gain Combustor Component Viability Assessment Based on Initial Testing

A review of recent testing has been performed to assess the viability of a wave-rotorbased pressure-gain combustor. Tests accomplished in 2009 at the Purdue Zucrow lab on the Wave Rotor Combustor Rig (WRCR) provide basic information on the combustion processes achievable in a wave rotor passage. During a 30 day test period, 34 successful tests were completed, the longest of which was a 3-second firing was completed which totaled nearly 2,000 individual combustion events. Analysis of the results indicated stable combustor operation. The operability of the device is assessed regarding stability and combustion speeds. Agreement with predicted operation is examined. Potential for successful integration into a gas turbine as a replacement of a conventional combustor is addressed.

An Experimental and Computational Study of Pulsed Detonations in a Single Tube

An experimental facility capable of operating multiple pulsed detonation tubes in cyclic fashion has recently been developed. The facility makes use of automotive valving via the head of a 4-cylinder Mitsubishi Eclipse engine. Thus far, cyclic detonations have been achieved in ethylene and propane air mixtures at frequencies up to 15 Hz. Numerical studies are also underway to compliment the experimental e orts. A computer program based on a Space-Time Conservation Element and Solution Element (CE/SE) method and a Low-Reynolds Number k turbulence model has been developed. Results of the simulations are presented at conditions similar to those in the experiments.

Emission Measurements and OH-PLIF of Reacting Hydrogen Jets in Vitiated Crossflow for Stationary Gas Turbines

An optically accessible gas turbine combustor test rig was constructed to study the combustion characteristics of a coaxial hydrogen/air jet injected into a vitiated swirl crossflow. The test rig has two combustion zones. The main combustion zone (MCZ) is a swirl stabilized dump combustor, and the secondary combustion zone (SCZ) is a reacting crossflow jet, referred to as the jet-in-crossflow (JIC). The SCZ is located downstream of the MCZ. The JIC is a coaxial hydrogen/air jet that penetrates radially into the vitiated stream. The combustor was designed to study the effects of JIC conditions on the SCZ combustion process and in particular on NOx production. The jet velocity and equivalence ratio were systematically varied. A water-cooled sampling probe was used to extract exhaust gases downstream of the SCZ for emission measurements. The JIC flame structure was captured by OH-PLIF images which show the extent of the flame front and the depth of penetration into the vitiated stream. The OH-PLIF images were averaged to determine the JIC reaction zone and were compared to the Holdeman correlation.© 2012 ASME