Carbon deposition model for oxygen-hydrocarbon combustion. Task 6: Data analysis and formulation of an empirical model

The formation and deposition of carbon (soot) was studied in the Carbon Deposition Model for Oxygen-Hydrocarbon Combustion Program. An empirical, 1-D model for predicting soot formation and deposition in LO2/hydrocarbon gas generators/preburners was derived. The experimental data required to anchor the model were identified and a test program to obtain the data was defined. In support of the model development, cold flow mixing experiments using a high injection density injector were performed. The purpose of this investigation was to advance the state-of-the-art in LO2/hydrocarbon gas generator design by developing a reliable engineering model of gas generator operation. The model was formulated to account for the influences of fluid dynamics, chemical kinetics, and gas generator hardware design on soot formation and deposition

Flight Hydrogen Sensor for use in the ISS Oxygen Generation Assembly

This paper provides a description of the hydrogen sensor Orbital Replacement Unit (ORU) used on the Oxygen Generation Assembly (OGA), to be operated on the International Space Station (ISS). The hydrogen sensor ORU is being provided by Makel Engineering, Inc. (MEI) to monitor the oxygen outlet for the presence of hydrogen. The hydrogen sensor ORU is a triple redundant design where each sensor converts raw measurements to actual hydrogen partial pressure that is reported to the OGA system controller. The signal outputs are utilized for system shutdown in the event that the hydrogen concentration in the oxygen outlet line exceeds the specified shutdown limit. Improvements have been made to the Micro-Electro-Mechanical Systems (MEMS) based sensing element, screening, and calibration process to meet OGA operating requirements. Two flight hydrogen sensor ORUs have successfully completed the acceptance test phase. This paper also describes the sensor s performance during acceptance testing, additional tests planned to extend the operational performance calibration cycle, and integration with the OGA system

Materials Combustion Testing and Combustion Product Sensor Evaluations in FY12

NASA Centers continue to collaborate to characterize the chemical species and smoke particles generated by the combustion of current space-rated non-metallic materials including fluoropolymers. This paper describes the results of tests conducted February through September 2012 to identify optimal chemical markers both for augmenting particle-based fire detection methods and for monitoring the post-fire cleanup phase in human spacecraft. These studies follow up on testing conducted in August 2010 and reported at ICES 2011. The tests were conducted at the NASA White Sands Test Facility in a custom glove box designed for burning fractional gram quantities of materials under varying heating profiles. The 623 L chamber was heavily instrumented to quantify organics (gas chromatography/mass spectrometry), inorganics by water extraction followed by ion chromatography, and select species by various individual commercially-available sensors. Evaluating new technologies for measuring carbon monoxide, hydrogen cyanide, hydrogen fluoride, hydrogen chloride and other species of interest was a key objective of the test. Some of these sensors were located inside the glovebox near the fire source to avoid losses through the sampling lines; the rest were located just outside the glovebox. Instruments for smoke particle characterization included a Tapered Element Oscillating Microbalance Personal Dust Monitor (TEOM PDM) and a TSI Dust Trak DRX to measure particle mass concentration, a TSI PTrak for number concentration and a thermal precipitator for collection of particles for microscopic analysis. Materials studied included Nomex(R), M22759 wire insulation, granulated circuit board, polyvinyl chloride (PVC), Polytetrafluoroethylene (PTFE), Kapton(R), and mixtures of PTFE and Kapton(R). Furnace temperatures ranged from 340 to 640 C, focusing on the smoldering regime. Of particular interest in these tests was confirming burn repeatability and production of acid gases with different fuel mixture compositions, as well as the dependence of aerosol concentrations on temperature

Landfill Gas Fueled HCCI Demonstration System

This demonstration system is intended to meet the California Energy Commission’s primary goal of improving California’s electric energy cost/value by providing a low-cost high-efficiency distributed power generation engine that runs on landfill gas. The project team led by Makel Engineering, Inc. includes UC Berkeley, CSU Chico and the Butte County Public Works Department.The team has developed a reliable, multi-cylinder Homogeneous Charge Compression Ignition (HCCI) engine by converting a Caterpillar 3116, 6.6 liter diesel engine to operate in HCCI mode. This engine utilizes a simple and robust thermal control system. Typically, HCCI engines are based on standard diesel engine designs with reduced complexity and cost based on the well known principles of engine dynamics. Coupled to an induction generator, this HCCI genset allows for simplified power grid connection.Testing with this HCCI genset allowed for the development of a control system to maintain optimal the inlet temperature and equivalence ratio. A brake thermal efficiency of 35.0% was achieved while producing less than 10.0 ppm of NOx and 30 kW of electrical power. Less than 5.0 ppm of NOx was recorded with a slightly lower brake thermal efficiency. Tests were conducted with both natural gas and simulated landfill gas as a fuel source. This demonstration system has shown that landfill gas fueled Homogeneous Charge Compression Ignition engine technology is a viable technology for distributed power generation

Landfill Gas Fueled HCCI Demonstration System

This demonstration system is intended to meet the California Energy Commission’s primary goal of improving California’s electric energy cost/value by providing a low-cost high-efficiency distributed power generation engine that runs on landfill gas. The project team led by Makel Engineering, Inc. includes UC Berkeley, CSU Chico and the Butte County Public Works Department.The team has developed a reliable, multi-cylinder Homogeneous Charge Compression Ignition (HCCI) engine by converting a Caterpillar 3116, 6.6 liter diesel engine to operate in HCCI mode. This engine utilizes a simple and robust thermal control system. Typically, HCCI engines are based on standard diesel engine designs with reduced complexity and cost based on the well known principles of engine dynamics. Coupled to an induction generator, this HCCI genset allows for simplified power grid connection.Testing with this HCCI genset allowed for the development of a control system to maintain optimal the inlet temperature and equivalence ratio. A brake thermal efficiency of 35.0% was achieved while producing less than 10.0 ppm of NOx and 30 kW of electrical power. Less than 5.0 ppm of NOx was recorded with a slightly lower brake thermal efficiency. Tests were conducted with both natural gas and simulated landfill gas as a fuel source. This demonstration system has shown that landfill gas fueled Homogeneous Charge Compression Ignition engine technology is a viable technology for distributed power generation