Pump jet with redirected exhaust gas through stator vane for drag reduction

摘要

An ETV-type pump jet having a stator housing with an attachment for minimizing the mismatches between the velocity and direction of the exhaust gas stream flowing out of a stator vane outlet and the velocity and direction of boat and pump jet motion. In one embodiment, a multiplicity of exhaust ducts are attached to the external surface of the stator housing, each exhaust duct being positioned to be in flow communication with the exhaust gas outlet of a respective hollow stator vane. Exhaust gases exiting the exhaust outlets are redirected by the inner surfaces of the ducts to flow in parallel with the rotor shaft axis. In another embodiment, a circumferential exhaust skirt made of sheet metal is substituted for the exhaust ducts. The exhaust skirt surrounds the stator housing and redirects the exhaust gas stream to be substantially parallel with the surrounding water flow.