ORCID Identifier(s)

0000-0002-3197-5447

Graduation Semester and Year

2021

Language

English

Document Type

Thesis

Degree Name

Master of Science in Aerospace Engineering

Department

Mechanical and Aerospace Engineering

First Advisor

Liwei Zhang

Second Advisor

Frank K Lu

Abstract

This thesis has two parts: 1) design of the streamline-traced inlets (STIs); and 2) integration of STIs with rotating detonation engines (RDEs). The STI design starts with a two-dimensional, isentropic compression flowfield as the parent flowfield. The method of characteristics was used to generate the flowfield throughout the entire STI. For a given flight altitude 18 km, freestream Mach number M?=3.0, and inlet exit-plane Mach number M?=1.2, a parametric sweep of the initial deflection angle ?1=4.0--11.0 deg and the Mach number at the entrance of the internal compression system M3=1.3--1.7 was performed to determine the STI performance sensitivity as a function of the design parameters. By using a variant of gradient-descent optimization, the optimal STI was chosen for the greatest combination of total pressure recovery and volumetric efficiency. By changing the type of internal compression system, two STIs were designed: STI-1 used a single-sided internal compression system, and STI-2 used a symmetrical internal compression system. At the design Mach number, it was found that STI-2 exhibited better performance than STI-1. The total pressure recovery of STI-2 was approximately five percent higher than that in STI-1. For volumetric efficiency, the difference between the STIs was marginal where STI-2 exceeded STI-1 by less than one percent. For the off-design cases, the commercial computational fluid dynamic package ANSYS Fluent was used to simulate the flowfields. The freestream Mach number was varied from 2.9 to 3.4. The freestream Mach number was limited to 3.4 due to the auto-ignition temperature of the RDE fuels. It was assumed that if the total temperature of the flow entering the RDE exceeded the minimum of the auto-ignition temperature range, the fuel would auto-ignite and not detonate as intended. For the range of freestream Mach number, the local Mach number and static pressure were determined at the inlet exit plane. In general, the total pressure recovery of both STIs exceeded the minimum established by MIL-E-5007D with exception of the subcritical speeds where both fell below the minimum. The total pressure recovery of STI-2 exceeded that of STI-1 throughout the entire range of Mach numbers. In the second part of the thesis, the integration of STI and RDE was explored. First, a parametric sweep was performed to select an RDE annulus configuration with the total pressure and total temperature obtained from the STI design. For both fuels considered, propane and hydrogen, the parametric sweep varied the engine annulus length l=15.0--50.0 cm to determine the RDE performance sensitivity as a function of design parameters. The RDEs were evaluated for their performance in regard to thrust, resultant torque, fuel-based specific impulse, and thrust-specific fuel consumption. A RDE annulus with a short length and wide thickness was chosen for both STIs using hydrogen as fuel. Second, the performance of the integrated STI/RDE systems were assessed. Internal ducting, including inlet isolator, was neglected; therefore, the total pressure value at the STI exit plane was used as the total pressure at the entrance of the RDE. For the chosen RDE annulus, over the entire range of Mach numbers, the RDE exhibited a slightly greater thrust for propane over hydrogen, and a slightly greater thrust for STI-2 than STI-1. For the resultant torque, hydrogen yielded a greater value than propane, and the RDE integrated with STI-2 exhibited a slightly greater torque than the system integrated with STI-1. For the fuel-based specific impulse, the cases with hydrogen were found to be approximately 2.3 times greater than the cases using propane. For the thrust-specific fuel consumption, the cases with propane were found to be approximately 2.4 times greater than the cases with hydrogen. There was no significant difference in the fuel-based specific impulse and thrust-specific fuel consumption for both STI designs. Within the context of this study, optimal performance was found for the STI-2 design utilizing hydrogen as the fuel.

Keywords

Supersonic inlets, Streamline-traced inlets, Rotating detonation engines

Disciplines

Aerospace Engineering | Engineering | Mechanical Engineering

Comments

Degree granted by The University of Texas at Arlington

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