Barrett

Barrett, The Honors College at Arizona State University proudly showcases the work of undergraduate honors students by sharing this collection exclusively with the ASU community.

Barrett accepts high performing, academically engaged undergraduate students and works with them in collaboration with all of the other academic units at Arizona State University. All Barrett students complete a thesis or creative project which is an opportunity to explore an intellectual interest and produce an original piece of scholarly research. The thesis or creative project is supervised and defended in front of a faculty committee. Students are able to engage with professors who are nationally recognized in their fields and committed to working with honors students. Completing a Barrett thesis or creative project is an opportunity for undergraduate honors students to contribute to the ASU academic community in a meaningful way.

Displaying 1 - 1 of 1
Filtering by

Clear all filters

Understanding Base Thrust of Highly Truncated Aerospike Nozzles

Description
This thesis examines how a recently proposed concept for a highly-truncated aerospike nozzle can be expected to perform at altitudes corresponding to ambient pressures from sea-level to full vacuum conditions, as would occur during second-stage ascent and during second-stage descent and return to Earth. Of particular importance is how the base pressure varies…

This thesis examines how a recently proposed concept for a highly-truncated aerospike nozzle can be expected to perform at altitudes corresponding to ambient pressures from sea-level to full vacuum conditions, as would occur during second-stage ascent and during second-stage descent and return to Earth. Of particular importance is how the base pressure varies with ambient pressure, especially at low ambient pressures for which the resulting highly underexpanded flows exiting from discrete thrust chambers around the truncated aerospike merge to create a closed (unventilated) base flow. The objective was to develop an approximate but usefully accurate and technically rooted way of estimating conditions for which the jets issuing from adjacent thrust chambers will merge before the end of the truncated aerospike is reached. Three main factors that determine the merging distance are the chamber pressure, the altitude, and the spacing between adjacent thrust chambers. The Prandtl-Meyer expansion angle was used to approximate the initial expansion of the jet flow issuing from each thrust chamber. From this an approximate criterion was developed for the downstream distance at which the jet flows from adjacent thrust chambers merge. Variations in atmospheric gas composition, specific heat ratio, temperature, and pressure with altitude from sea-level to 600 km were accounted for. Results showed that with decreasing atmospheric pressure during vehicle ascent, the merging distance decreases as the jet flows become increasingly under-expanded. Increasing the number of thrust chambers decreases the merging distance exponentially, and increasing chamber pressure results in a decrease of the merging distance as well.
ContributorsHerrington, Katie (Author) / Dahm, Werner (Thesis director) / Takahashi, Timothy (Committee member) / Barrett, The Honors College (Contributor) / Mechanical and Aerospace Engineering Program (Contributor) / Department of Physics (Contributor)
Created2024-05