Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / A theoretical study is presented of the fluid mechanics of the inlet vortex (or ground vortex) phenomenon. The vorticity field associated with the vortex is investigated using a secondary flow approach. In this approach the flow is assumed to be composed of an irrotational primary flow and a weak shear flow, with the vortex filaments associated with the latter being regarded as convected by the former. The potential flow field induced by the inlet-ground plane combination is computed using the panel method developed by · Hess, Mack and Stockman. Using the analysis, material lines (which coincide with vortex lines) can be tracked between a far upstream location, where this vorticity can be taken as known, and the engine face location. The deformation of the material lines thus shows directly the generation and amplification of the streamwise component of vorticity, which is responsible for the velocity distortion at the compressor face. Two representative flow configurations are considered, one with headwind only and one with the flow at forty-five degrees to the inlet axis of symmetry. Although the results so far yield only qualitative information, they appear to provide some insight into one mechanism associated with the inlet vortex formation. / by Henri Charles Viguier. / M.S.

The aerodynamic and thermodynamic performance of an aircraft gas turbine directly affects the fuel consumption of the engine and the life of the turbine components. Hence, it is important to be able to understand and predict the fluid flow and heat transfer in turbine blades to enable the modifications and improvements in the design process. The use of numerical experiments for the above purposes is becoming increasingly common. The present thesis is involved with the development of a flow solver for turbine flow and heat transfer computations. A 3-D Navier-Stokes code, the Moore Elliptic Flow Program (MEFP) is used to calculate steady flow and heat transfer in turbine rotor cascades. Successful calculations were performed on two different rotor profiles using a one-equation q-L transitional turbulence model. A series of programs was developed for the post-processing of the output from the flow solver. The calculations revealed details of the flow including boundary layer development, trailing edge shocks, flow transition and stagnation and peak heat transfer rates. The calculated pressure distributions, losses, transition ranges, boundary layer parameters and peak heat transfer rates to the blade are compared with the available experimental data. The comparisons indicate that the q-L transitional turbulence model is successful in predicting flows in transonic turbine blade rows. The results also indicate that the calculated loss levels are independent of the gridding used while the heat transfer rate predictions improve with finer grids. / Master of Science

The focus of this research is to numerically predict an infrared image of a jet engine exhaust plume, given field variables such as temperature, pressure, and exhaust plume constituents as a function of spatial position within the plume, and to compare this predicted image directly with measured data. This work is motivated by the need to validate Computational Fluid Dynamic (CFD) codes through infrared imaging. The technique of reducing the three-dimensional field variable domain to a two-dimensional infrared image invokes the use of an inverse Monte-Carlo ray trace algorithm and an infrared band model for exhaust gases. This dissertation describes an experiment in which the above-mentioned field variables were carefully measured. Results from this experiment, namely tables of measured temperature and pressure data, as well as measured infrared images, are given. The inverse Monte-Carlo ray trace technique is described. Finally, experimentally obtained infrared images are directly compared to infrared images predicted from the measured field variables. / Ph. D.