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, scramjets, rotating detonation engines.
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).
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.
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.
Below are a few examples from our ongoing work in four principal areas: (1) Propulsion (rockets, gas turbines, scramjets, rotating detonation engines), (2) Combustion (detonation physics, turbulent combustion, thermo-acoustic instabilities), (3) Fluid mechanics (turbulence, acoustics, multi-phase and supercritical flows), and (4) optical diagnostics (signal processing, advanced laser sources, cross-platform verification and validation). 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.