Dual Flow Nozzle Thrust Stands
Channel 11 & 14 Dual Flow Static Nozzle Thrust Stands
Used to evaluate dual stream exhaust system performance at static conditions. Exhaust system models are mounted on a direct connect balance. A three component force balance measures thrust, normal force, and pitching moment. Two ASME flow meters determine the mass flow delivered to the core flow and the fan flow of a turbofan model and the momentum needed for the force balance equation. The core flow is heated to simulate the effect of combustion and mixing on the nozzle performance. The maximum temperature ratio is Tcore/Tfan=2.5.
Exhaust System Mixing
Thrust and pressure loss performance for exhaust systems with mixed core and bypass flow can be acquired in Channel 11 or 14.
Reverse Thrust Evaluation
Cascade and target type thrust reverser systems are evaluated in the facility for reverse thrust effectiveness and exhaust plume characteristics.
Acoustics
Exhaust flow from a turbofan engine model is measured using microphones located on an arc or linear array centered at the nozzle exit for relative noise levels between test configurations.
Channel 11 and 14 are hot / cold dual-flow static thrust stands used to determine performance of exhaust nozzles in which the two exhaust flows are at different temperatures. Nozzle thrust is determined from force measurement with a strain-gage force balance.
The airflows for both the cold and hot passages of a test nozzle are obtained from the facility 500-psi dry air storage system. Air for the cold passage is throttled, metered through a long-radius ASME nozzle, ducted to the cold passage of the test nozzle, and finally exhausted to atmosphere. Air for the hot passage is throttled, passed through a regenerative storage heater, mixed with unheated bypass flow to achieve a desired temperature, metered through a long-radius ASME nozzle, ducted to the hot passage of the test nozzle, and finally exhausted to atmosphere.
The air heater used for the hot flow contains alumina pebbles which are preheated to approximately 1150 °F with a combustion heater.
Facility instrumentation is provided to calculate mass flow rates at core flow meter and the fan flow metering locations, and to calculate the exit thrust produced by the test nozzle. The test data include measurements of axial and vertical balance forces, air mass flow rates, model total and static pressures, and the air temperatures and pressures necessary to calculate the flow rate and stream thrust entering the metric portion of the model assembly.
Flow conditions for static tests are set by independently regulating the airflow to the fan and core meters to obtain the desired Ptfan/Pambient and Ptcore/Pambient.
The fan and core nozzle model air is preheated to room temperature for cold-flow tests. For hot-flow tests, the core nozzle model air is preheated to achieve the desired temperature ratio.
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