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The gas flow rate is constant (i.e., steady) during the period of the propellant burn. The gas flow is non-turbulent and axisymmetric from gas inlet to exhaust gas exit (i.e., along the nozzle's axis of symmetry). The flow is compressible as the fluid is a gas. As the combustion gas enters the rocket nozzle, it is traveling at subsonic velocities.
Grossly overexpanded nozzles have improved efficiency, but the exhaust jet is unstable. Conventional nozzles become progressively more underexpanded as they gain altitude. [1] The basic concept of any engine bell is to efficiently direct the flow of exhaust gases from the rocket engine into one direction.
Diagram of a de Laval nozzle, showing approximate flow velocity (v), together with the effect on temperature (T) and pressure (p) A de Laval nozzle (or convergent-divergent nozzle, CD nozzle or con-di nozzle) is a tube which is pinched in the middle, with a rapid convergence and gradual divergence.
Pump curves are quite useful in the pump selection, testing, operation and maintenance. Pump performance curve is a graph of differential head against the operating flow rate. They specify performance and efficiency characteristics. Performance tests are done on the pumps to verify the claims made by the pump maker.
A supersonic flow that is turned while there is an increase in flow area is also isentropic. Since there is an increase in area, therefore we call this an isentropic expansion. If a supersonic flow is turned abruptly and the flow area decreases, the flow is irreversible due to the generation of shock waves.
Different types of pumps are suitable for different applications, for example: a pump's maximum lift height also determines the applications it can be used for. Low-lift pumps are only suitable for the pumping of surface water (e.g., irrigation, drainage of lands, ...), while high-lift pumps allow deep water pumping (e.g., potable water pumping ...
Expander rocket cycle. Expander rocket engine (closed cycle). Heat from the nozzle and combustion chamber powers the fuel and oxidizer pumps. The expander cycle is a power cycle of a bipropellant rocket engine. In this cycle, the fuel is used to cool the engine's combustion chamber, picking up heat and changing phase.
Cutaway side-view diagram of an axial piston pump 3-D rendering of an axial piston pump with the parts labeled Animation of an axial piston pump in operation. An axial piston pump has a number of pistons (usually an odd number) arranged in a circular array within a housing which is commonly referred to as a cylinder block, rotor or barrel.