Deep-throttle static test results from an and hydroxyl-terminated polybutadiene hybrid rocket motor are presented. The nominal 800 N thrust level was turned down to less than 12 N while still maintaining stable and controlled combustion. This turndown was accomplished using a commercial off-the-shelf throttle valve and a solid rocket motor case adapted for hybrid rocket testing. During throttled motor tests, the pressure ratio across the injector grows from a nominal value of 2.0 to greater than 3.0. This feature contrasts with the observed behavior of liquid rockets, where the injector pressure ratio drops significantly during deep throttle. This characteristic likely supports the observed hybrid burn stability during deep throttle. Data comparisons with a physics-based, throttled, hybrid rocket burn model accurately match for combustor pressure, thrust, and propellant consumption. At throttle levels approaching 20% of nominal, the exiting the throttle valve is entirely in a vapor state. The vapor chokes the injector and eliminates feed system coupling. This two-phase effect is another likely reason for the unexpected combustion stability observed at very deep-throttle levels. The ability to throttle deeply opens the possibility that hybrid thrusters could be simultaneously deployed for both main spacecraft propulsion and reaction control.
Deep Throttle of a Nitrous Oxide and Hydroxyl-Terminated Polybutadiene Hybrid Rocket Motor
Journal of Propulsion and Power ; 30 , 1 ; 78-86
01.01.2014
Aufsatz (Konferenz) , Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
Deep Throttle of a Nitrous Oxide and Hydroxyl-Terminated Polybutadiene Hybrid Rocket Motor
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