Handbook of Turbomachinery Second Edition Revised - Ventech!

a gear train that has performed satisfactorily in over 2,500 production
units. The experience gained to date in turbomachinery design was also
evident. At approximately 5 1
2 hp per pound of weight, the Thor engine
turbopump more than doubled the specific power of its Redstone predecessor.
During the mid- and late 1950s, this geared turbopump arrangement
was a common design selection used by several aerospace companies.
Several distinct variations emerged. Among these were
A common pump drive where a single gear train linked the turbine to
both pumps. This arrangement was used where both pumps could operate at
the same angular velocity.
Independent gear drives where each pump was geared separately to the
turbine. This arrangement allowed each pump to run at a different angular
velocity. This could be necessary for a number of reasons, such as a large
density difference between propellants.
Turbine direct drive to one propellant pump, with a gear train to the
other propellant pump. This arrangement was particularly applicable to an
engine that had a large difference in the power requirements for the two
pumps. It has the potential to avoid large reductions in turbopump system
efficiency caused by a low-power design for a separate turbine for the lowpower
pump.
It should be pointed out that the original necessity for gear drive of a
turbopump was the inability of the centrifugal pumps to operate at the same
angular velocity as the turbine. This was due to a number of factors, all
based on fundamental technology that did not exist in the 1950s. The U.S.
government and industry have invested considerable effort in research since
that time. As a result, the obstacles that made gear drives necessary are now
largely absent. For this reason, a ‘‘common shaft’’ arrangement with both
pump(s) and turbine on the same shaft is now essentially a standard. This
configuration obviously benefits in both weight and bulk from the absence
of the gearbox and the internal gear train.
In the late 1950s, the U.S. government perceived the need to develop a
very high thrust single-chamber rocket engine. This perception was based on
understanding (and speculation) of the propulsion capability of the Soviet
Union at the time. The engine was to produce 1.5 million lb of thrust
burning liquid oxygen and kerosene propellants. This engine was the F-1. A
cluster of five such engines provided the first-stage muscle for the Saturn V
launch vehicle and until the late 1980s was the most powerful operational
rocket engine in the world. To support the engine thrust level of over
750 tons, enormous quantities of propellants had to be moved from the
vehicle tanks to the thrust chamber. With the combustion chamber pressure
set at approximately 1,000 psi, 2 tons of liquid oxygen per second had to be
Copyright © 2003 Marcel Dekker, Inc.