Engineering Commons^™

Engineering Model To Calculate Mass Flow Rate Of A Two-Phase Saturated Fluid Through An Injector Orifice, Brian J. Solomon

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

An engineering model is developed to calculate mass flow rate of nitrous oxide, a self-pressurizing saturated oxidizer commonly used in hybrid rocket motors. While use of N_{2}0 cannot be accurately modeled using traditional ideal gas, compressible, or incompressible flow assumptions. To obtain accurate mass flow rate this one-dimensional analysis includes both incompressible fluid and homogeneous equilibrium mass flow rate models. Mass flow calculations from the two models are independently weighted and summed to obtain representative two-phase mass flow rate. Fluid properties are iterated in time by keeping track of fluid enthalpy and are propagated across the injector using either isentropic …

Nonlinear Aerodynamic Corrections To Blade Element Momentum Model With Validation Experiments, Robert S. Merrill

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

Blade element momentum theory is well suited for propeller analysis during the early stages of design. The analytic blade element momentum model is presented along with a proposed nonlinear improvement. The analytical model makes small angle assumptions which are known to be inaccurate under some conditions. The nonlinear model avoids these assumptions. The results of the analytical and nonlinear models are compared against each other. The differences between these are most prevalent on lower pitch propellers at high advance ratios. A wind tunnel validation test is outlined. Results of the validation test and other published data from the University of …

Optimization Of A Low Reynold's Number 2-D Inflatable Airfoil Section, Todd A. Johansen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A stand-alone genetic algorithm (GA) and an surrogate-based optimization (SBO) combined with a GA were compared for accuracy and performance. Comparisons took place using the Ackley Function and Rastrigin's Function, two functions with multiple local maxima and minima that could cause problems for more traditional optimization methods, such as a gradient-based method. The GA and SBO with GA were applied to the functions through a fortran interface and it was found that the SBO could use the same number of function evaluations as the GA and achieve at least 5 orders of magnitude greater accuracy through the use of surrogate …

A 6-Degree Of Freedom Static Thrust Stand Developed For Rc-Scale Jet Engines, Spencer Sessions

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

The description of a portable 6-degree of freedom static thrust stand for RC-scale jet engines is reported. The stand includes three axial and three lateral load cells measuring static thrust with six degrees of freedom. A pitot probe with single axis position control placed perpendicular to exhaust flow measures stagnation pressure along the nozzle centerline. A pitot probe open to the inside of the engine nozzle normal to the exhaust flow and near the outlet measures static pressure. A digital scale measures fuel consumption. The engine is mounted with exhaust gases exiting upward avoiding ground effects and thrust acting downward. …

Computational Efficiency Of A Hybrid Mass Concentration And Spherical Harmonic Modeling, Nathan Piepgrass

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Through Spherical Harmonics, one can describe complex gravitational fields. However as the order and degree of the spherical harmonics increases, the computation speed rises exponentially. In addition, for onboard applications of spherical harmonics, the processors are radiation hardened in order to mitigate negative effects of the space environment on electronics. But, those processors have outdated processing speeds, resulting in a slower onboard spherical harmonic program.

This thesis examines a partial solution to the slow computation speed of spherical harmonics programs. The partial solution was to supplant the gravity models in the flight software. The spherical harmonics gravity model can be …