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Centrifugal compressors find their use in many areas especially in turbochargers which are used extensively in automobiles and in aircrafts and defence systems. This paper presents the design of a complete test facility for testing centrifugal compressors. It starts with design of a Combustor - the driving unit for the test facility. The Centrifugal compressor being tested is a part of a turbocharger. The combustor feeds the Turbine side of the test section with hot gases for running the compressor at desired speeds. This particular choice eliminates the need for the inclusion of heavy speed reducing gears when an electric motor is used as the driving unit. The designed combustor was numerically simulated and subsequently optimized for the given working conditions. The simulated results showed good agreement with the target criteria. Further, the choice and placement of the measuring instruments for the entire test rig and their permissible deviations are listed and finally the basic operating sequence for the entire rig is also drafted for in-house development of automation of the entire test rig thereby making it a complete guide for the setting up of such facility, hitherto establishing a complete guideline of all subsystems which will enable in building such similar facilities in varying magnitudes in the future.

Fuel injection system influences the spray characteristics to achieve faster combustion and better control over emissions. The combination of orifice number, diameter, injection duration, and rotation is suggested for better emission control and efficiency. In the present work, a novel self-rotating injector is designed and fabricated. Simulation is performed in three-dimensional closed-cycle geometry of a 661 cc diesel engine for static as well as rotating fuel injection having three, five, and nine holes by varying the rotational speed of 1500 and 2500 rpm, orifice diameter, and injection duration to ensure the same injection velocity. The three-hole rotating cases were studied and compared with static numerical simulation. The results found that due to the rotational effect, the engine’s thermal efficiency improved by 3.82% and 5.11% while the NOx emissions decreased by 2.34% and 5.57% for 1500 and 2500 rpm, respectively, at the cost of carbon monoxide and soot emissions. Increasing the rotational speed was found to improve temperature uniformity at higher speeds, thus increases the efficiency and lower NOx. By increasing the number of orifice holes, it was observed that both thermal efficiency and NOx increased. Controlling the primary and diffusion combustion, it is possible to improve the efficiency without increasing NOx emissions. This was possible with a combination of rotating injectors and varying the start of injection. The fabricated self-rotating nozzle based on the above simulations was found to perform better than the static injector under no-load conditions.

This research aims to study the trajectory of an object inside a serpentine duct of a gas turbine engine using computational fluid dynamics. The coupled implicit solver with 6-degree of freedom (6-DOF) and chimera mesh (Overset mesh) is used to track the object’s trajectory. Various object orientation and aircraft angle of attack (AoA) at a speed of Mach 0.3 is studied. This provides an understanding of the bird’s movement inside the duct that might cause damage to the engine components during takeoff and landing. It was observed that the combination of AoA and object orientation decide the length of the trajectory before impact. The object is found to travel the farther when the AoA is at -20o with object oriented at 0o and 45o.The object tends pitch and yield to the flow irrespective of its initial orientation and hence the aircraft angle of attack is a more predominant factor. The effect of pressure recovery due to AoA and object orientation is also presented. The recovery is found to be at its best for AoA of 0o irrespective of object orientation. This approach could be utilised for designing an intake duct that can limit the damage to engine components due to bird ingestion and simultaneously maintain good pressure recovery.

Improving engine performance is a constant challenge and various methodologies have been adopted by researcher’s world over. In this work, the dispersion characteristics of a rotating injector is studied by varying the umbrella angle (UA) followed by its combustion characteristics and comparing it to a static 3 – hole injector. The present numerical study is bench marked with the experimental data obtained from open literature for a 2 – hole injector with various umbrella angles. The volume fraction of the dispersed fuel along with its spray structure in relation to spray width is compared. This is done by processing the numerical contour plot using LabView image processing utility with appropriate calibration. From this study the 130 degree UA injector configuration was found to be effective when compared with 70. The combustion characteristics is now studied for this injector. It is found that the rotating injector has better dispersion and lowers NOx by 14 % when compared to a static injector with a very marginal loss in thermal efficiency. The rotary system has a lower heat release but a wider spread in comparison to a static case. This helps in marginally reducing the in-cylinder temperature and pressure lower NOx.

Breast cancer is a common and dreadful disease among women. Regular screening helps in its early detection. At present the most common methods of screening are self-examination and mammography. The surface temperature distribution of the breast can also provide some information on the presence of an underlying tumour. This distribution has a relation to the size and location of tumour and can be seen using thermography, where the infrared radiation emitted from the surface of the breast is recorded and a thermal pattern obtained. Thermography is a non-invasive and an inexpensive tool, which could be used for early detection. The aim is to develop not only a tool that is affordable, but also reliable in detecting breast cancer. It is hoped that the surface temperature pattern obtained using thermography along with numerical simulation will provide a reasonable idea about the size and location of the tumour. Doctor of Philosophy (MPE)