Compressor Delivery Research Articles

Powerplant: Installation

The engine bay is formed by the sides and undersurface of the fuselage and extends from the nosegear bay back to main gear bay. The engine bay is divided nto two zones (Fig. 4) by a fireproof bulkhead mounted on the engine at the joint between the h.p. compressor delivery casing and the combustion chamber casing. Zone 1 (forward of the bulkhead) contains the compressor sections of the engine, the engine fuel system, oil tank and the engine driven accessories.

Pressure Pulsations in Reciprocating Compressor Delivery Systems

In an earlier paper (1)†, the author discussed the nature of pressure pulsations in suction systems of free-piston gas generators, and in particular various forms of pulsation damping devices. A theoretical approach was based on a simple linear treatment of the system, i.e. (1) regarding all pressure pulsations as small in relation to the mean pressure on which they are superimposed, (2) treating dissipative elements (pipe friction or concentrated restrictions) as having linear pressure drop-velocity relationships about the mean flow condition, and (3) treating all distributed elements as having wave motion in accordance with small wave (2) or acoustic theory (rather than the non-linear finite wave theory (3) (4)). Although the physical conditions in compressor delivery systems are very different from those in gas generator suction systems, a similar theoretical approach, verified by acoustic model tests, has been found both to provide a good insight into the problem, and to give an acceptably accurate quantitative indication of pressure pulsation amplitudes. For this purpose systems have been divided into: (1) lumped impedance systems, (2) distributed impedance systems.

Induction Ramming of Small High-Speed Air Compressor

The paper describes an investigation of the effects of piston-excited pressure waves in the plain induction pipe of a small, high-speed, single-cylinder air compressor. For a range of pipe lengths and diameters, compressor speeds and delivery pressures, the observed compressor throughput and driving torque are compared with those obtained with no intake pipe fitted. Based on classical laws of wave motion but using an experimentally obtained steady-flow characteristic for the inlet valve, a theoretical treatment is developed to describe the pressure pulsations in the inlet port and cylinder and to predict the change in airflow resulting from the fitting of any particular intake pipe. Experimentally recorded indicator diagrams compare satisfactorily with those predicted theoretically and similar agreement is obtained between the experimental and theoretical values of airflow. An 18 per cent increase in airflow is reported.