Pump power density is the power density of the pump expressed in watts per kilogram. As of 2001; the space shuttle main engine turbopump has the highest power density, one hundred and sixty thousand watts watts per kilogram, of any turbopump in use. Rocket pumps have higher power densities than pumps in typical use, because they have the combustion of liquid oxidizers and liquid fuels to tap. This high power density heat source leads to high power density in either evaporative engines which indirectly tap the heat of the rocket engine or combustion engines which directly tap the heat of combustion. Also, rocket engines are generally designed for high power density at the expense of a shorter service life.

The pump power density can be increased by opening up its design, operating the pump at higher temperatures, operating its components at higher tip speeds, testing many designs and using light materials like ceramics. Operating a pump at a higher power tends to reduce its service life and decrease its reliability, increasing its effective cost. The pump power density is used to calculate the pump cost and the pump mass.

pump mass = pump power / pump power density

pump cost = pow( ( pump power density / 160,000 ), pump density scale ) * pow( ( pump power / 10,000,000 ), structure mass scale ) * ten megawatt price
 
 

This is used in pumped rocket and rocket cost.
 
 

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