Arcjet rocket

About: Arcjet rocket is a research topic. Over the lifetime, 1121 publications have been published within this topic receiving 9687 citations. The topic is also known as: Arcjet.

Advanced materials for thermal protection system

Abstract: Reticulated open‐cell ceramic foams (both vitreous carbon and silicon carbide) and ceramic composites (SiC‐based, both monolithic and fiber‐reinforced) were evaluated as candidate materials for use in a heat shield sandwich panel design as an advanced thermal protection system (TPS) for unmanned single‐use hypersonic reentry vehicles. These materials were fabricated by chemical vapor deposition/infiltration (CVD/CVI) and evaluated extensively for their mechanical, thermal, and erosion/ablation performance. In the TPS, the ceramic foams were used as a structural core providing thermal insulation and mechanical load distribution, while the ceramic composites were used as facesheets providing resistance to aerodynamic, shear, and erosive forces. Tensile, compressive, and shear strength, elastic and shear modulus, fracture toughness, Poisson’s ratio, and thermal conductivity were measured for the ceramic foams, while arcjet testing was conducted on the ceramic composites at heat flux levels up to 5.90 MW/m2 (520 Btu/ft2⋅sec). Two prototype test articles were fabricated and subjected to arcjet testing at heat flux levels of 1.70–3.40 MW/m2 (150–300 Btu/ft2⋅sec) under simulated reentry trajectories.

Hollow cathodes in high pressure arc discharges

Abstract: An orified hallow cathode was tested at high pressure to improve lifetime and efficiency in arcjet thrusters. It is indicated that the arc would not operate with emission from the insert above 200 torr in nitrogen regardless of insert material, orifice diameter, or gas flow direction. Emission occurred from the insert in argon and xenon although it could not be ascertained whether diffuse or spot emission existed within the cathode. Over the extended range of configurations and operating parameters explored the desired diffuse emission mode could not be obtained at high enough pressures for orified hollow cathodes to operate in the range which is considered for arcjet applications.

A Collimated Total Radiation Probe for Arcjet Measurements

Abstract: The total energy radiation of an argon arcjet was measured by a simple collimated thermopile. Radiation from the luminous jet was found to vary as T7.2 when the peak (centerline) temperature at the arcjet exit plane was 12,600°K. Total radiated energy from the arcjet, including the downstream-directed component from the cathode face, was found to agree quite well with theoretical estimates given in the present paper. The use of a purified helium atmosphere and lithium fluoride optical components permitted achievement of transmissivity down to 1060 angstroms on all measurements.

Effects of insulator ablation on the operation of a quasi-steady MPD arc

Abstract: Multimegawatt operation of quasi-steady MPD arcjets can involve serious ablation of the insulator surfaces within the arc discharge chamber. Various degrees of insulator ablation manifest themselves by significantly perturbing the voltage-current characteristics and the exhaust velocity profiles. Voltage-current characteristics for two different insulator materials, Plexiglas and boron nitride, are interpreted in terms of an empirical Ohm's law. Use of the refractory insulator material eliminates the ablation-dominated nature of the terminal voltage, but the exhaust stream is still disturbed by insulator material. An Alfven critical velocity model can be applied to this influence of insulator ablation on exhaust velocity. Appropriate changes in the propellant injection geometry eliminate this influence and result in arcjet operation which is independent of insulator material. A particular combination of propellant injection geometries reduces the terminal voltage for a given current and mass flow while maintaining insulator-independent operation, thus implying an improvement in the overall efficiency of the device.

A small thrust measurement system of electric thruster

Abstract: A small thrust measurement method was presented in theory for precision measurement of small thrust of low power electric thruster, namely when thrust measure balance is in the state of indifferent equilibrium (or near to the state of indifferent equilibrium), electromagnetism force feedback compensation can eliminate the influence of connection of gas line and electric wire and feedback electromagnetism force can compensation thrust of thruster. Thrust values of different operational mode of arcjet thruster were measured. Experiment validated that this measure method can measure small thrust of electric thruster accurately.