Photoflash and laser ignition of full density nano-aluminum PVDF films

Heat balance evaluation of double-base solid propellant combustion using thermography and laser heating on a burning surface

Photoflash and laser ignition of Al/PVDF films and additively manufactured igniters for solid propellant

The objective of this work was to study the near-surface phenomena of an energetic binder, butanetriol trinitrate/ glycidyl azide polymer, during thermal decomposition and combustion. A triple quadrupole mass spectrometer with microprobe sampling was used to obtain gas-phase quantitative species from CO 2 laser-induced decomposition and laser-assisted combustion of the butanetriol trinitrate/glycidyl azide polymer sample. To get the species profile as a function of height from the surface, a linear positioner was used to move the sample towards the microprobe during sampling. Fine-wire thermocouples were used to get the surface temperature and gas-phase temperature profile in the primary flame zone. The experiments were conducted at a laser heat flux of 35 W/cm 2 and in both argon environment and ambient air conditions with varying pressures from 1.0 to 4.0 atm. The flame structure and burning event were recorded using a digital camcorder so that the burning rates at these pressures can also be determined.

Laser-Driven Decomposition and Combustion of BTTN/GAP

This paper describes experimental work on laser-controlled combustion of solid propellants. Combustion of AP/HTPB, including ignition, combustion, extinction and re-ignition could be controlled by CO2 laser irradiation at the back pressure of 0.1, 0.3 and 0.5 MPa in nitrogen. Burning rate of propellant increased linearly with the increasing of laser power density. Vieilles law was used here to check pressure effect to burning rate, pressure exponent under different power density (except 0.5 MW/m2) are very close to 0.17.

Laser-Controlled Combustion of Solid Propellant

This paper describes experimental work on laser-assisted combustion and its use to control solid propellants. Burning rates of hydroxyl-terminated polybutadiene and ammonium perchlorate composite solid propellants were measured at pressures up to 90 kPa under laser irradiation, and propellant-preheat temperature distribution was measured by thermography. Combustion control, including ignition and interruption by laser irradiation, was feasible with custom-made (fuel-rich) non-self-combustible solid propellants with a burning rate coincident with Vieille's law and a pressure exponent of approximately 0.5. Consequently, this combustion-control concept seems to be applicable to a microsatellite thruster. The heat balance on the burning surface evaluated at a laser power density of 1.4 W ·mm -2 at 50 kPa produced the following results: chemical reaction was endothermic at a heat flux of -0.7W mm -2 , heat was supplied to the solid phase of the propellant at a heat flux of 3.7 W ·mm -2 , and heat-feedback rate to the burning surface was 3.0 W ·mm -2 , which suggests that approximately 70% of the energy transferred to the burning surface was provided by combustion itself, and the laser supplied supplementary heat flux to compensate for the heat insufficiency to sustain combustion.

Laser-Assisted Combustion of Solid Propellants at Low Pressures

This paper describes experimental work on laser-assisted combustion and its control of solid propellants. Burning rates of HTPB/AP composite solid propellants were measured at pressures up to 90 kPa under laser irradiation coupled with the propellant preheat temperature distribution measured by thermography. With custom made (fuel-rich) non-self combustible solid propellants, the combustion control, including ignition and interrupting by the laser irradiation, was feasible having the burning rate coincident with Vieille’s law and a pressure exponent of approximately 0.5, and therefore, this combustion control concept seems to be applicable to a thruster such as one for microsatellites. The heat balance on the burning surface evaluated with a laser power density of 1.4 W/mm 2 at 50 kPa was 1)the chemical reaction was endothermic at a produced heat flux of -0.7 W/mm 2 , 2)the heat was supplied to the solid phase of the propellant at a heat flux of 3.7 W/mm 2 , and 3)the heat feedback rate to the burning surface was 3.0 W/mm 2 , which suggest that approximately 70% of the energy to the burning surface was provided by the combustion itself, and the laser supplied the supplementary heat flux to compensate for the heat insufficiency for combustion sustenance.

Ryoma Hiyamizu

Papers

Laser-Assisted Combustion of Solid Propellants at Low Pressures

Laser-assisted combustion of solid propellants