Abstract

Aerospace vehicles often experience triboelectric charging while traversing the atmosphere. Triboelectric charging occurs when a material come into frictional contact with a different material. Aerospace vehicles triboelectrically charge due to frictional contact with dust and ice crystals suspended in the atmosphere. Launch vehicles traversing ice clouds in low-pressure atmosphere are especially prone to electrostatic discharge events (i.e. sparks). These conditions are hazardous and affect the vehicle's launch commit criteria. In 2010, engineers from an ARES-I rocket launch reported concerns with triboelectric charging over their self-destruct system antenna. This concern was addressed by putting the antenna through harsh conditions in a laboratory environment. The need for laboratory testing could have been avoided if there was a mathematical model to predict these events. These discharge events can typically be predicted by the Classical Paschen's Law, which relates discharge voltage to pressure, material and distance between the charged and ground surfaces (i.e. electrodes). However, the Classical Paschen's Law does not capture any aerodynamic considerations such as large bulk flow and compressibility effects. It became apparent that a new model would be needed to predict a discharge voltage with aerodynamic considerations. This research focused on defining a theoretical model and providing experimental data to validate the model. The hypothesis of this work is that charged ions are removed too quickly for enough charge to build up and result in an electrostatic discharge at the voltage that is predicted by the Classical Paschen's Law. The wind tunnel testing for this experiment was conducted at the Center for Advanced Turbomachinery & Energy Research (CATER) facility. A charged electrode was exposed to flows at Mach numbers 1.5 to 3.5. It was found that the supersonic flow suppressed the electrostatic discharge events. The voltage required for an electrostatic discharge at supersonic conditions increased by a factor of three. The modified Paschen's Law can help in defining the launch commit criteria of aerospace vehicles.

Notes

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Graduation Date

2018

Semester

Spring

Advisor

Ahmed, Kareem

Degree

Master of Science in Aerospace Engineering (M.S.A.E.)

College

College of Engineering and Computer Science

Department

Mechanical and Aerospace Engineering

Degree Program

Aerospace Engineering; Thermofluid Aerodynamic Systems

Format

application/pdf

Identifier

CFE0007059

URL

http://purl.fcla.edu/fcla/etd/CFE0007059

Language

English

Release Date

May 2018

Length of Campus-only Access

None

Access Status

Masters Thesis (Open Access)

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