NASA 1998 SBIR Phase I

PROPOSAL NUMBER: 98-1 07.02-2100

PROJECT TITLE: UV Dual-band Photodiode Sensors for Dynamic Combustion Control


This Phase I SBIR proposal addresses the NASA need for minimally invasive aircraft sensors which are simple in implementation and yet insightful as diagnostic tools. The project is aimed at the development of a robust optical sensor for real-time monitoring of aircraft engine combustion dynamics. The sensor consists of two photodiode elements designed to respond in different wavelength bands corresponding to the emission from various electronically excited radical species generated in the combustion process. One photodiode element of the sensor monitors UV emission which originates from the oxygen containing species hydroxyl radical, OH, and carbon monoxide, CO. The other element is sensitive to emission which comes primarily from hydrocarbon radicals such as C2 and CH. The intensity ratio from the two photodiode elements provides data on the dynamics of the combustion process such as the air-to-fuel mix ratio. The photodiode sensors are made from group-III nitride materials. Photodiodes made from these materials are highly responsive to the ultraviolet emissions in combustion flames, but are insensitive to the background visible and infrared radiation from hot engine components. The group-III nitrides are also extremely inert and robust, which make them ideal for high temperature, harsh environment applications.


In addition to its application in jet aircraft combustion diagnostics, the technology developed during this program could also be applied to ground based turbine engines such as those in electrical power generation, or to marine turbine engines on ships. This technology could be valuable in other sectors as well. An example is in UV flame sensing in bright solar background. The military has interest in detection of missiles or artillery fire by observing the UV emission in the flames associated with these weapons. The important criteria in this case is to discriminate the UV emission from the weapons against the solar background. The CO and OH sensing photodiode would be valuable in this regard. Also, there is need for robust UV irradiance meters for use in the semiconductor and UV curing industries. The group-III nitride materials developed under this program will be far superior to existing silicon-based devices and will find numerous applications in these fields.


Jody J. Klaassen
SVT Associates, Inc.
7620 Executive Drive
Eden Prairie , MN 55344


SVT Associates, Inc.
7620 Executive Dr.
Eden Prairie , MN 55344