Pintled nozzle

Fig. 15.4 shows a schematic representation of a nozzle throat area controller used in a VFDR. The mass flow rate from the nozzle attached to the primary combustion chamber (gas generator) to the secondary combustion chamber (ramburner) is changed by inserting a pintle. The high-temperature gas produced in the gas generator flows into the ramburner through the pintled nozzle. The pintle inserted into the nozzle moves forward and backward in order to alter the nozzle throat area. As the nozzle throat area is made small, the mass flow rate increases according to the concept described above. The fuel-flow rate becomes throttable by the pintled nozzle. 

Keywords Momentum ratio Pintle nozzle Rocket injector... 

SMD = CpA Vl (pm), c=25.1,23.9, 22.4 for pintle,hole,throttiingpiulle nozzles, resp. Liquid jet from a diesel-type injector into quiescent air, A-Pf. (MPa), Pa (kg/rn3), (mm3/stroke) HiroyasuA Kadotil3 ]... 

Fig. 15.4 A nozzle throat area controller based on insertion of a pintle into the throat.

Fuel injectors are nozzles that inject a spray of fuel into the intake air. They are normally controlled electronically. A metered amount of fuel is trapped in the nozzle end of the injector, and a moderate injector pressure (2—3 bar) generated by a fuel pump is applied to it At the proper time, the nozzle is opened and fuel is sprayed into the intake manifold. The amount of injected fuel is controlled by pressure and dwell time of injection. An electronic fuel injector consists of solenoid coil, valve needle, plug, fuel inlet, and pintle. When not activated, flie cod spring holds the plunger against its seat, which blocks the inlet flow of fuel. When activated, the electric solenoid coil is excited and moves the plunger and pintle. This opens the needle valve... 

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