Research activities in Propulsion have been pursued at the Department since its inception in 1967. The Department is also the only one to offer a post graduate specialization in Propulsion amongst all similar departments in India.
The field of air-breathing propulsion involves various branches of science and engineering. However, only those involving aerodynamics, computational fluid dynamics, aerothermodynamics, structural analysis and materials technology are being pursued at the Department.
Past research studies have been funded mainly by the Propulsion Panel of the Aeronautics Research and Development Board, and have addressed problems related to gas turbine combustion, turbine heat transfer, blade vibration, rotor vibration, fuel control systems, engine sizing, transonic axial compressors, contra-rotating axial fans, tandem cascades, and turbine material lifing. Each of these studies has formed part of at least one funded research program, supported multiple post graduate students, and lead to publications in national as well as international conferences and journals.
Apart from the above problems in the field of air-breathing propulsion, some of the basic sciences underlying the propulsion field have been applied to the study of fluid flow and heat transfer in the callandria of a nuclear reactor, and in the development of a spirometer for biomedical applications.
Present research focuses on swept blades for axial compressors, hypersonic propulsion unit, compressor blade loss modeling, multistage transonic compressor performance prediction, transonic blade profile CFD analysis, gas turbine engine material lifing, CFD analysis of engine intakes, engine component analysis, infrared signature of aircraft engines, stall/surge prediction/indication, and hypersonic aircraft heat transfer. The links below give brief descriptions of some of this work.
Aerodynamic Heating in Aerospace Vehicles
As part of ongoing work, a computer code is being developed to predict the time -- temperature history of an entire hypersonic vehicle. Analysis of critical regions like sweptback leading edges has revealed significant differences in the behavior of aerodynamic heating. Part of the work focuses on the optimization of the insulating thermal protection system for a hypersonic vehicle.
Microchannel Cooling of Gas Turbine Blades
Basic investigations of behavior of fluid flow & heat transfer at micro scale revealed significant qualitative differences as compared to the macro scale. The effects that surface at the micro scale are being numerically identified. Some of these effects have fundamental repercussions in the understanding of the macro scale behavior as well. At present optimization of micro scale heat sink is in progress in the Department.
Aerothermal Flow Analysis of the Propulsion Unit of Hypersonic Aircraft
Ongoing work at the Department focuses on analysis leading to design of a propulsion unit for a hypersonic aircraft. The work involves analysis of various components and performance optimization over the given trajectory.
Modeling of losses in axial-flow compressors
As part of work funded by Pratt and Whitney, losses incurred in the rotors and stators of a multi-stage compressor were mathematically modeled. Separate modeling was required for two- and three-dimensional flows. The work resulted in a computer code for computing overall compressor performance based on these loss models.
A Novel Infrared Signature Suppression System for Helicopter Engines
Work done at the department has resulted in the conceptualization of an unconventional Infrared Signature Suppression System (IRSS) for helicopter engines. The new IRSS yields a maximum contrast of only 25 deg C with the local background from almost all the view angles of concern. In other words, the IRSS ensures that a helicopter engine operating at the most most critical point of the mission would appear hotter than the surroundings by not more than 25 deg C, making it extremely difficult for a heat-seeking missile to lock on to the helicopter. Without a signature suppressor, the temperature contrast between the engine and the surroundings would exceed 400 deg C. The temperature contrast achieved by the new IRSS is far superior to almost all the IRSS devices reported in open literature, which claim a minimum temperature contrast of 80 deg C. In addition, the reported IRSS devices have relatively significant back-pressure and weight penalties that effectively increase the IR Signature level of the helicopter since the engine has to operate at a higher combustion temperature to overcome the penalties without compromising the mission. In contrast, the IRSS conceptualized in the department has no back-pressure penalty, and an insignificant weight and drag penalty.Part of the work involved making a thermal model that simulates the multi-mode heat transfer including radiation interchange using analytical view factors for discretized geometry.
Some of the research work conducted using propulsion lab facility is outlined below: