Numerical Analysis of Energy Conversion Process via Laser Supported Detonation Wave in Pulse Laser Propulsion

Paper number

IAC-05-C4.6.04

Author

Dr. Hiroshi Katsurayama, University of Tokyo, Japan

Coauthor

Prof. Yoshihiro Arakawa, University of Tokyo, Japan

Coauthor

Dr. Kimiya Komurasaki, University of Tokyo, Japan

Year

2005

Abstract

There is a strong demand to frequently deliver payloads to space at a
low cost. A pulse laser powered vehicle will be able to satisfy this
demand: The payload ratio would be improved drastically because energy
 is provided from a laser base on the ground to the vehicle.
In addition, once a laser base is constructed, the cost is only
electricity charges.
the vehicle is accelerated to reach the orbital velocity through a
 pulsejet, ramjet and rocket mode. The pulsejet
 and the ramjet utilize atmospheric air as propellant, and rocket does
on-board hydrogen propellant.

In pulse laser propulsion, a gas-breakdown occurs by focusing a
transmitted laser beam.
The front of produced plasma absorbs the following part of laser beam
and expands in the form of Laser Supported Detonation (LSD) wave.
After laser intensity decays to a LSD threshold, the shock wave in front
of the LSD wave separates from the plasma front and the plasma expands
in the form of Laser
Supported Combustion (LSC) wave.

A part of laser energy absorbed by the LSD process is used
to directly drive the shock wave (blast wave), and is efficiently converted to thrust
work, while LSC process is inefficient because the absorbed energy is not
converted to blast wave energy.
Thereby, the mechanism of the LSD-LSC transition should be clarified to
predict the performance of a pulse laser powered vehicle.

The LSD has the mechanism similar to chemical
detonation. The detonation wave is driven by the electrons behind the shock
absorbing the laser energy, which are produced maily by the
photo-ionization due to radiation from the laser absorption layer.
However, the mechanism is not clarifed quantitatively.

We will compute the propagation of laser supported waves by the 2-D CFD
code with laser-plasma interaction, multi-ionization and photo-inozaion
processes in order to clarify the mechanisms of the driving LSD and
LSD-LSC transition. In addition, the conversion efficiency from laser
energy to blast wave energy are investiagted in reduced atomospheric air
and hydrogen propellant.

Abstract document

IAC-05-C4.6.04.pdf

Manuscript document

IAC-05-C4.6.04.pdf (🔒 authorized access only).

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