Pump efficiency is the power of the pump divided by the power available in the tapped gases. The losses in a typical turbine & compressor combination occur in the turbine used to tap the power and in the compressor used to pressurize the propellants. Another method of using the available power is to spin the rocket engines around a pivot and pressurize the reactants with centrifugal force. This is extremely efficient; but, requires rotating seals.

In general pump efficiency can be increased by careful machining, opening up its design and testing many designs. Pump efficiency is used along with the propellant usage and the working temperature to calculate the propellant energy which is in turn used to calculate the pump boost.

propellant energy = propellant usage * pump efficiency * working temperature * 8,314 J * K / kmol / 0.2
 

combustion exhaust = combustion ratio / exhaust molecular

uncombustion = 1.0 - combustion ratio

pump energy = propellant energy * propellant mass ratio / propellant molecular + propellant energy * reactant propellant usage * ( fuel mass ratio * ( uncombustion / fuel molecular + combustion exhaust ) + oxidizer mass ratio * ( uncombustion / oxidizer molecular + combustion exhaust ) )

pump boost = pump energy / pump need
pump power = pump energy * fuel flow
 
 

This is used in astropolis, pumped rocket and rocket cost.
 
 

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