Auxiliary power unit with pulse detonation combustion
AssigneePratt & Whitney Canada Corp.
InventorDaniel Alecu
Life of this patent
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Abstract
An accessory power unit assembly includes a combustor assembly that includes a pulse detonation tube that defines a curved passage between an inlet that receives a compressed airflow and a discharge end. The detonation tube operates as a resonant cavity to sustain a standing pressure wave. Fuel injected into the pulse detonation tube is timed to coincide with movement of a standing wave toward a discharge end. The standing wave provides an increase in pressure of an output exhaust gas driving the turbine without a corresponding increase in load.
Claims20
An accessory power unit assembly comprising:
- a compressor coupled to an engine shaft disposed about an engine axis;
- a combustor assembly configured to generate an exhaust gas flow, the combustor assembly including at least one detonation tube defining a curved passage between an inlet receiving a compressed airflow and a discharge end, wherein the combustor assembly further includes at least one fuel injector configured to inject fuel into the inlet;
- an igniter for igniting a fuel air mixture within the detonation tube near the discharge end;
- and
- a turbine coupled to the engine shaft configured to rotate in response to the exhaust gas flow communicated from the combustor assembly.
A gas turbine engine comprising:
- a compressor coupled to an engine shaft disposed about an engine axis;
- a diffuser receiving compressed airflow from the compressor;
- a distribution manifold receiving the compressed airflow from the diffuser;
- a combustor assembly including:
- at least three detonation tubes, wherein each of the detonation tubes define a curved passage between an inlet and a discharge end, wherein the inlet includes an outer rounded cross-section and an inner converging/diverging venturi and is orientated transverse to an inlet flow of air such that air flows across the inlet;
- a fuel injector configured to inject fuel into the inlet;
- and
- an igniter for igniting a fuel air mixture within the detonation tube near the discharge end;
- and
- a turbine coupled to the engine shaft configured to rotate in response to an exhaust gas flow communicated from the combustor assembly.
A method of operating an auxiliary power unit assembly comprising:
- generating a standing pressure wave between an inlet and discharge end of a curved detonation tube;
- measuring a pressure differential between the inlet and a downstream location;
- injecting a quantity of fuel through the inlet in response to the measured pressure differential indicating a reversal of the standing pressure wave toward the discharge end;
- igniting a fuel air mixture with an igniter upon reaching a location proximate the discharge end;
- and
- discharging an exhaust gas flow through the discharge end to drive a turbine.
Dependencies are inferred from the claim text.