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The goal of this research is to apply modern methods of analysis to the design of a tungsten-cermet Nuclear Thermal Rocket (NTR) core. An NTR is one of the most viable propulsion options for enabling piloted deep-space exploration. Concerns over fuel safety have sparked interest in an NTR core based on tungsten-cermet fuel. This work investigates the capability of modern CFD and neutronics codes to design a cermet NTR, and makes specific recommendations for the configuration of channels in the core. First, the best CFD practices available from the commercial package Star-CCM+ are determined by comparing different modeling options with a hot-hydrogen flow experiment. Next, through grid convergence and sensitivity studies, numerical uncertainty is shown to be a small contributor to overall uncertainty; while fuel thermal conductivity, hydrogen specific heat, and fission energy deposition are found to have a large impact on simulation uncertainty. The model-form error is then estimated by simulation of a NERVA fuel element from an NRX-A6 engine test, where the peak temperature matches measured data to within 2.2%. Using a combination of Star-CCM+ and MCNP for neutronics, typical uncertainties are estimated at 3% for predicting fuel temperature, 2% for hydrogen temperature, and 5% for pressure. The second part uses the aforementioned analysis methods in a parametric study to determine what coolant channel size and distribution is optimum for a 10 klbf-thrust cermet NTR core. By varying the channel diameter and pitch-to-diameter ratio (p/d), it is found that a diameter of 0.12 cm with a p/d of 1.8 results in the lightest core with a peak temperature of 2850 K. The study also shows that element-by-element mass flow rate zoning is the best method for handling radial power peaking. In addition, a detailed simulation of a cermet design developed at the Argonne National Laboratory shows that modifications to the historical fuel element design are required to avoid overheating. The final part investigates the ability of Star-CCM+ to model fuel element failure modes. Through a combination of uncertainty quantification and a parametric analysis, this thesis ultimately lays a groundwork for future detailed design of cermet NTR fuel elements.

154 leaves : ill., photos ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Physics, 1976

Thesis (Ph. D.)--Virginia Polytechnic Institute, 1963. / Vita. Abstract. Includes bibliographical references (leaves 54-56). Also available via the Internet.

Thesis (M.S. in Mechanical Engineering)--Naval Postgraduate School, December 2002. / Thesis advisor(s): Ashok Gopinath. Includes bibliographical references (p. 81-82). Also available online.

Thesis (M.S.)--California Polytechnic State University, 2009. / Mode of access: Internet. Title from PDF title page; viewed on September 23, 2009. Major professor: William R. Murray. "Presented to the faculty of the College of Engineering, California Polytechnic State University, San Luis Obispo." "In partial fulfillment of the requirements for the degree [of] Master of Science in Mechanical Engineering." "September 2009." Includes bibliographical references (p. 80).

Thesis (M.S.)--California Polytechnic State University, 2009. / Mode of access: Internet. Title from PDF title page; viewed on September 28, 2009. Major professor: William Murray, Ph.D. "Presented to the faculty of California Polytechnic State University, San Luis Obispo." "In partial fulfillment of the requirement for the degree [of] Master of Science in Mechanical Engineering." "September 2009." Includes bibliographical references (p. 49-50).

Thesis (M.S.)--University of Missouri--Rolla, 2007. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed October 24, 2007) Includes bibliographical references (p. 95-98).

The exhaust plumes generated by rocket motors are of significant military importance for missile detection, recognition and communication due to their electromagnetic emission and propagation properties. The plume is a high temperature, high velocity stream of gas and particles, into which the surrounding air is entrained. With improvements in the modelling of plume gas chemistry and turbulence, particles present in the plume have become more important in the computational prediction of the plume's flow field, and the subsequent prediction of plume emission and propagation characteristics. This thesis describes research on plume particles, including the measurement of their physical characteristics and the addition of two phase coding (ie. particles) into current plume prediction software. Particle collections were carried out in plumes produced by rocket motors with double base and composite propellants (including aluminised). The collected particles were analysed to establish their chemical composition and size distribution. A laser Doppler anemometer system was successfully used to measure particle velocities in the plumes of 1.5kN double base motors. Particle tracking software was used to trace the paths of particles using a simplified prediction of the plume and it was found that the predicted particle behaviour was analogous to that measured experimentally. Project management software was used during the research and its relevance was assessed in respect to the project's size and nature. The management of experimental trials was studied and a methodology formulated to help improve their future operation. The costs and benefits of the research were assessed and compared to other research projects. Many of the benefits gained, such as measurement techniques, require marketing to ensure that they are exploited in the future. Recommendations for future research are given that should enhance the present work.

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