Laser igniter, method for igniting high pressure and dilute fuel-oxidizer mixtures
The invention provides method for igniting pressurized fuel, the method comprising placing fuel into a combustion chamber; mixing the fuel with supercritical carbon dioxide and oxidizer to create a mixture; and contacting the fuel-air mixture with a laser, whereby the laser is pointed to a first point within the chamber. Also provided is a laser ignitor for carbon dioxide combustors, the ignitor comprising: an elongated housing capable of varying in length, the housing having a first proximal end and a second distal end; a laser head in close spatial relationship to the proximal end, wherein the laser head generates a first laser beam; a seal at the distal end that is optically transparent to the laser beam and physically opaque to combustion contaminants; an algorithm for directing the first beam to a first point within a combustion chamber for a first period of time; and an algorithm for directing a second laser beam to a second point within the combustion chamber for a second period of time.
1 . A method for igniting pressurized fuel, the method comprising:
a) placing fuel into a combustion chamber;
b) mixing the fuel with supercritical carbon dioxide and oxidizer to create a fuel-oxidizer mixture;
c) aligning a laser head with an axis of a lens disposed in an outer tube of an elongated housing, wherein a portion of an inner tube is disposed in the outer tube and a portion of the inner tube is exterior to the outer tube;
d) physically decoupling the inner tube from the laser head subsequent to aligning the laser head with the axis of the lens by telescoping the portion of the inner tube exterior to the outer tube into the outer tube, wherein heat transfer back to the laser head is reduced; and
e) contacting the mixture with a first laser beam emitted by the laser head, whereby the first laser beam is pointed to a first point within the chamber for a first period of time.
2 . The method as recited in claim 1 , wherein the first laser beam is constant.
3 . The method as recited in claim 1 , wherein the first laser beam is not constant.
4 . The method as recited in claim 1 , comprising: changing focus of the first laser beam to a plurality of points throughout the combustion chamber over time.
5 . The method as recited in claim 1 , wherein a temperature of the combustion chamber is between 20° C. and 800° C.
6 . The method as recited in claim 1 , wherein a second laser is pointed to a second point within the chamber.
7 . The method as recited in claim 1 , wherein no physical hardware associated with the first laser beam protrudes into the chamber.
8 . The method as recited in claim 1 , wherein the first point comprises a first node of the fuel-oxidizer mixture within the chamber.
9 . The method as recited in claim 6 , wherein the second point comprises a second node of the fuel-oxidizer mixture within the chamber.
10 . The method as recited in claim 1 , wherein the first point comprises a first physical surface within the chamber.
11 . The method as recited in claim 6 , wherein the second point comprises a second physical surface within the chamber.
12 . The method as recited in claim 1 , comprising:
using a plurality of laser pulses in succession to increase temporal ignition kernel distribution and improve ignition probability.