Local Heat Flux Measurements with Single Element Coaxial Injectors

Abstract

To support the mission for the NASA Vision for Space Exploration, the NASA Marshall Space Flight Center conducted a program in 2005 to improve the capability to predict local thermal compatibility and heat transfer in liquid propellant rocket engine combustion devices. The ultimate objective was to predict and hence reduce the local peak heat flux due to injector design, resulting in a significant improvement in overall engine reliability and durability. Such analyses are applicable to combustion devices in booster, upper stage, and in-space engines, as well as for small thrusters with few elements in the injector. In this program, single element and three-element injectors were hot-fire tested with liquid oxygen and ambient temperature gaseous hydrogen propellants a t The Pennsylvania State University Cryogenic Combustor Laboratory from May to August 2005. Local heat fluxes were measured in a 1-inch internal diameter heat sink combustion chamber using Medtherm coaxial thermocouples and Gardon heat flux gauges. Injectors were tested with shear coaxial and swirl coaxial elements, including recessed, flush and scarfed oxidizer post configurations, and concentric and non-concentric fuel annuli. This paper includes general descriptions of the experimental hardware, instrumentation, and results of the hot-fire testing for three of the single element injectors -recessed-post shear coaxial with concentric fuel, flush-post swirl coaxial with concentric fuel, and scarfed-post swirl coaxial with concentric fuel. Detailed geometry and test results will be published elsewhere to provide well-defined data sets for injector development and model validatation.https://ntrs.nasa.gov/search.jsp?R=20060047645 2018-05-13T07:45:23+00:00Z

Measurement of Transient Heat Flux and Surface Temperature Using Embedded Temperature Sensors

“…1 Domains addressed by current theory: a) finite slab, b) finite slab with sensor on second surface, c) semi-infinite slab, and d) internal points. @ 2 T @x 2 1 @T @t (2) As shown by Burggraf [15], the heat equation can be extended to any even-numbered derivative of x:…”

“…Sensor failure rates are high, and measurement accuracies and uncertainties are not well characterized. These shortcomings have had a significant impact on some recent programs that have used heat-sink test articles to acquire data for the validation of heat transfer predictions at liquid rocket engine operating conditions [1,2].…”

High flowrate injector with gaseous hydrogen and gaseous oxygen

“…Presently, the reliability and the reusability of future engines have become more and more important. The heat fluxes and the compatibilities of specific injectors have been lucubrated to increase the engine lifecycles [14][15][16]. Additionally, the FFSC engine is particularly designed for long lifecycle and high reliability.…”

Method for Measurement of Single-Injector Heat Transfer Characteristics and Its Application in Studying Gas-Gas Injector Combustion Chamber

“…The heat-sink chamber is preferable (Calhoon, 1973;Marshall et al, 2005;Conley et al, 2007;Jones et al, 2006) in the initial design phase of a new injector or in the study on the heat transfer characteristics of injector owing to its simple structure, low cost and easy manufacture. Thus, heat-sink combustion chamber was selected in this study.…”

“…In recent years, Pennsylvania State University, University of Florida and NASA MSFC etc. made many attempts on studying the heat transfer characteristics of some injectors in heat sink chambers (Conley et al, 2007;Jones et al, 2006;Marshall et al, 2005;Vaidyanathan et al, , 2010b. They applied coaxial thermocouple to measure two point temperatures at the same axial location and difference radial locations in a heat-sink copper combustion chamber, and then used the temperatures to calculate the local heat flux through a simple radial heat conduction analytical calculation.…”