THE SLABAUGH GROUP
Advanced Propulsion and Combustion Research
Advanced Propulsion and Combustion Research
From the Laboratory to the Engine.

ABOUT THE RESEARCH GROUP

We seek to understand the coupled nonlinear physics and chemistry of combustion through complementary experimental and analytical approaches. Our research program covers a wide range of topics; from the fundamental exploration of turbulence-chemistry interactions to the development of advanced combustion technologies for liquid rocket engines. The group also maintains a continuous effort in the advancement of high-bandwidth (typically, laser-based) measurement techniques to non-intrusively probe the physics of these complex, reacting flows. Our current work is funded by government as well as private sources, represented below.

Our laboratory is housed within the Zucrow Laboratory complex. The high pressure, high flow-rate system capabilities enable experimental replication of the flame conditions (pressure, turbulence level, thermal power density) found in today's most advanced propulsion and energy systems. In addition to our academic endeavors, we also work with industrial sponsors on testing programs to characterize and advance the performance of propulsion systems such as rockets, gas turbines, (sc)ramjets, rotating detonation engines.

  See Our Work

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THE TEAM

Carson

Prof. Carson Slabaugh

Principal Investigator

Rohan

Dr. Rohan Gejji

Post-Doctoral Research Associate

Aaron

Aaron Lemcherfi

Research Engineer

Andrew

Andrew Pratt

Research Engineer

Buschhagen

Timo Buschhagen

PhD Student

Duntz

Lt. Mark Duntz

MS Student, AFIT/PMRI

Frederick

Mark Frederick

PhD Student, NSF Fellow

Funari

Vincent Funari

MS Student

Journell

Chris Journell

PhD Student

Philo

John Philo

PhD Student

Schwinn

Kyle Schwinn

PhD Student

Walters

Ian Walters

PhD Student

Zhang

Robert Zhang

PhD Candidate

Plaehn

Ethan Plaehn

Undergraduate RA

Strelau

Ryan Strelau

Undergraduate RA

LABORATORY

Our experimental research is enabled by the extensive and unique infrastructure in place at the Zucrow High Pressure Laboratory. The Purdue University Zucrow Laboratories have a longstanding history of large-scale experimental capabilities. Originally built for the purpose of rocket testing in the 1940s, the lab underwent a transformation to also support air-breathing experiments in the late 1960s. An air-plant provides a 0.45 kg/s continuous supply of dry, clean compressed air at 15 MPa while simultaneous access to 9000 kg (also at 15 MPa) is available to support higher mass flow rates. Main, secondary, and tertiary channels provide up to five independently controlled and metered air supplies to the any given experiment. Three independent heat exchangers are available to preheat clean, dry, nonvitiated, high-pressure air supplies for testing at representative engine conditions (up to 1100 K at 6 MPa).

Aerial photograph of the Zucrow High Pressure Laboratory.

An equally capable inert gas system has also been integrated for experiment purges, pneumatic controls, and other unique system needs. Liquid nitrogen boil-off is pumped to 40 MPa at a rate of 0.05 kg/s for continuous operation, while over 9000 kg of gaseous nitrogen is stored at 40 MPa for higher rates of consumption. Fuel can be sourced from large bulk storage systems as well as bottle (or drum) manifolds when it is necessary to run chemically-pure or specially-blended fuels. Gaseous and liquid fuel systems have been integrated to support steady-state flame conditions in excess of 10 MW total thermal power. A high pressure cooling water system is also available for test article cooling and hot-gas quenching needs. The system is capable of providing a steady-state output of 5 kg/s of water at 8.3 MPa, with a 350 L high pressure, emergency reserve.

High-pressure methane-air RDE firing in test cell 3.  This 20MW combustor was the first combustor to operate in our new facility.

Our experiments are supported by a series of test rig platforms that enable the rapid development, integration, and operation of new concepts. All testing operations are contained within isolated test cells with 20 inch thick reinforced concrete walls and steel explosion-proof doors. While a facility battery backup and generator system minimize the probability of an uncontrolled shutdown, all systems are designed to achieve a de-energized, default state in the case of power loss or emergency. Facility, test-article, and measurement (including laser diagnostic) systems are all controlled remotely over the secure Zucrow HPL secure intranet. A National Instruments (NI) LabView Virtual Instrument (.vi) is developed for live control of the experiment and data acquisition (at up to 1000 Hz). The .vi also serves as a live redline monitoring system, with automatic abort operations programmed for emergencies such as a drop in cooling water flow rate or a spike in a monitored temperature (e.g. indicating a flashback). Experiment set-points, such as equivalence ratio, are calculated in real time for live tuning of experimental conditions. High frequency pressure data is also recorded with an independent data acquisition system (recording at over 2 MHz). The high frequency data acquisition systems dedicated analog-to-digital converters and signal conditioning for each channel to support simultaneous measurements from up from sixty-four instruments.

As a cornerstone of our research program, a competitive arsenal of high speed laser sources and detection equipment is also maintained. Currently available are three continuous duty-cycle diode-pumped solid state (DPSS) systems to support laser-based measurements at up to 40 kHz sampling frequencies. A pulse-burst laser (PBL) is also available within the Zucrow High Pressure Laboratory. Built by Spectral Energies, it is capable of providing LPSS pulse-energy levels at 10 kHz repetition rates for approximately 10 ms burst durations. The repetition rate of the PBL can be extended to (and beyond) 100 kHz with roughly comparable total power; providing the ultimate research laser source in terms of flexibility and energy density.

41 MPa
Propellant Supplies (6000 psi)
8 MW
Thermal Power (with windows)
45 kN
Thrust (10000 pound-force)
100+ kHz
Optical Measurements

RESEARCH

Below are a few examples from our ongoing work in three principal areas: (1) Combustion and Propulsion (rockets, gas turbines, rotating detonation engines), (2) Fluid Mechanics, and (3) Optical Diagnostics. Click on an image for a brief description and a list of selected publications. For a complete list of publications, please refer to the PI's Google Scholar page.

<p style=text-align:left;> Rotating detonation engines represent the most promising technology for realization of pressure gain combustion.  Our group has several active programs focused on both fundamental and applied aspects of these systems.</p>
	  <p style=text-align:left;font-size:85%> <u>Select Publications:</u></p>
      <p style=text-align:left;font-size:75%> Kyle Schwinn, Rohan Gejji, Brandon Kan, Swanand Sardeshmukh, Stephen Heister, and Carson D. Slabaugh. Self-Sustained, High-Frequency Detonation Wave Generation in a Semi-Bounded Channel. Combustion and Flame, 193:384–396, 2018. doi: 10.1016/j.combustflame.2018.03.022.</p>
<p style=text-align:left;> The three-dimensional structure of turbulent reacting flows is highly-dynamic, and it exists across a wide range of time-scles and length scales.  Turbulence acts to promote transport of heat, mass, and momentum within the flow, affecting a net increase in the rate of rectant mass consumption by the flame.  In return, the flame modifies the flow through changes in the thermo-chemical and thermo-physical properties of the fluid.  The large-scale properties of a flame are manifested by these small-scale interactions, which have a highly-nonlinear sensitivity to the local stength and extent of perturbations to both physical and chemical processes.  Our work in turbulent combustion spans from fundamental canonical flames to engine-scale combustors.  Thermo-acoustic instabilities (such as the one shown) are a sub-set of the problems we study in this area.</p> 
	  <p style=text-align:left;font-size:85%> <u>Select Publications:</u></p>
      <p style=text-align:left;font-size:75%> Robert Zhang, Andrew C. Pratt, Robert P. Lucht, and Carson D. Slabaugh. Structure conditioned velocity statistics in a high pressure swirl flame. Proceedings of the Combustion Institute, 2018.</p>
      <p style=text-align:left;font-size:75%> Timo Buschhagen, Rohan Gejji, John Philo, Lucky Tran, Enrique Portillo-Bilbao, and Carson D. Slabaugh. Self-excited transverse combustion instabilities in a high pressure lean premixed jet flame. Proceedings of the Combustion Institute, 2018</p>
      <p style=text-align:left;font-size:75%> Carson D. Slabaugh, Isaac Boxx, Stephanie Werner, Wolfgang Meier, and Robert P. Lucht. The Structure and Dynamics of Premixed Swirl Flames at Elevated Power Density. AIAA Journal, 54(3):946–961, 2016. doi: 10.2514/1.J054294</p>
      <p style=text-align:left;font-size:75%> Carson D. Slabaugh, Claresta N. Dennis, Isaac Boxx,Wolfgang Meier, and Robert P. Lucht. 5 kHz Thermometry in a Swirl-Stabilized Gas Turbine Model Combustor using Chirped Probe Pulse Femtosecond CARS. Part 2: Analysis of Swirl Flame Dynamics. Combustion and Flame, 173:454–467, 2016. doi: 10.1016/j.combustflame.2016.02.032.</p>
<p style=text-align:left;> High-speed laser diagnostics can provide critical information about reacting flows.  We develop and apply imaging techniques, such as particle image velocimetry (PIV) and planar laser-induced fluorescence (PLIF), to characterize the structure of the fluid flow, the progress of chemical reactions, and the dynamics of these coupled processes.  We apply spectroscopic techniques, such as coherent anti-Stokes Raman scattering (CARS), to quantitatively measure fluid properties such as temperature, pressure, and species concentration.  Shown above is a three-dimensional reconstruction of the large-scale flow structures that were measured in a high-pressure swirl flame using stereoscopic PIV.  The flow is oscillating severely due to a thermo-acoustic instability.</p>
   	  <p style=text-align:left;font-size:85%> <u>Select Publications:</u></p>
      <p style=text-align:left;font-size:75%> Claresta N. Dennis, Carson D. Slabaugh, Isaac Boxx, Wolfgang Meier, and Robert P. Lucht. 5 kHz Thermometry in a Swirl-Stabilized Gas Turbine Model Combustor using Chirped Probe Pulse Femtosecond CARS. Part 1: Experimental Measurements. Combustion and Flame, 173:441–453, 2016. doi: 10.1016/j.combustflame.2016.02.033.</p>
      <p style=text-align:left;font-size:75%>  Carson D. Slabaugh, Andrew C. Pratt, and Robert P. Lucht. Simultaneous 5 kHz OH-PLIF/PIV for the study of turbulent combustion at engine conditions. Applied Physics B: Lasers and Optics, 118(1), 2015. doi: 10.1007/s00340-014-5960-5.</p>
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