Internal Flow Field Structure in a Simulated Fin-Slot Region of a Rocket Motor

Jeffrey D. Moore, Peter J. Ferrara, Robert B. Wehrman, Ryan W. Houim, Kenneth K. Kuo

Research output: Contribution to conferencePaperpeer-review

5 Scopus citations

Abstract

To understand the flow characteristics in a fin-slot propellant grain section, a study parallel to flame-spreading rate measurements is being conducted. The purpose of the current study is to gain better knowledge of the flow structure in the fin-slot region, which has confined spaces and complex geometry. The flow from the igniter jet has significant influence on the recirculating pattern due to its impingement angle and degree of underexpansion. A subscale (approximately l/10 th) pie-shaped fin-slot motor was designed to simulate the head-end fin-slot segment of the reusable solid rocket motors (RSRM) of the Space Shuttle booster, and to perform diagnostic measurements for studying the flow field structure on the exposed inert propellant surfaces. The simulation motor consisted of a single triangular fin section mounted in a stainless-steel chamber with observation windows. Clean air was compressed and passed through a blow-down wind tunnel for supplying the air to flow through the igniter section and enter the fin-slot region. The igniter nozzle of this simulated rocket motor was designed to achieve the same expansion angle, impingement point, and flow rate as the approximately 1/10 th scale live igniter in the first segment of the RSRM. Experimentally, flow field visualizations were conducted by two different techniques. Flow surface visualization was achieved by applying a chalk-powder/kerosene mixture to the inner surface of the sacrificial window. The flow directional pattern was also identified using many small threads taped to various locations covering the entire viewing area of the fin-slot region for high-speed video camera recording. Theoretically, CFD simulations were conducted using Fluent Software for modeling the flow field in the internal region of the test rig. Results showed that the theoretical and experimental internal flow field directional patterns were similar in nature. The increase in core flow conditions from transient to steady-state operation had a profound effect on the internal flow field patterns. The observed and calculated flow field structure helped to provide useful information for the studying the flame-spreading process in the fin-slot region of the propellant grain.

Original languageEnglish (US)
StatePublished - Dec 1 2005
Event41st AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit - Tucson, AZ, United States
Duration: Jul 10 2005Jul 13 2005

Other

Other41st AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit
CountryUnited States
CityTucson, AZ
Period7/10/057/13/05

All Science Journal Classification (ASJC) codes

  • Aerospace Engineering
  • Control and Systems Engineering
  • Electrical and Electronic Engineering

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