Aerospace Engine Testing - The Sky's the Limit [Application Note]

Published by Cyndi Rude   – June 14, 2016

Hoffer Flow Controls The Hoffer custom The smaller turbine has been awarded a contract to supply turbine flowmeters to a major U.S. space agency. The turbine flowmeters will be used to test large propulsion engines. We are pleased to be a part of this program.

The customer specifying the turbine flowmeters has been playing a key support role since the early 1960's with work on the Saturn program. Upon completion of the Apollo and Skylab programs, this customer's role in engine testing moved to the next step in space travel -- the Space Shuttle. Using its three large
Apollo era test stands with thrust capability to 15 million pounds, this location's primary mission is to test and flight certify the Space Shuttle's main engines, which power the vehicle during its eight and one-half minutes of flight prior to orbit. This particular location began testing the main engines in June, 1975.

This customer is currently prepared to test much of the propulsion hardware for future launch vehicles at its state-of-the-art component test facility. Their flexible,three-celled ground test facility will be capable of a wide variety of testing including rocket engine testing using liquid hydrogen, cryogenic liquids and hydrocarbon fuels. Capabilities also include testing with ultra-high pressure gases.

The Hoffer custom designed turbine flowmeters will be installed in their component test facility. The flowmeters will range in sizes from 2" through 16". The 12" and 16" turbine flowmeters will be used to test the shuttle's main engine which operates at greater temperature extremes than any other mechanical system in common use today. To fuel the engine, liquid hydrogen (-423 degrees Fahrenheit), is combined with liquid oxygen (-297 degrees Fahrenheit). When ignited, they produce a temperature in the engine's combustion chamber that reaches +6,000 degrees Fahrenheit, higher than the boiling point of iron.

The smaller turbine flowmeters supplied by Hoffer will be used for super critical liquid oxygen, and super critical liquid hydrogen gases. Flow rates will be extremely high and the meters are designed with custom rotor assemblies incorporating shallow blade angles on the rotor to minimize the RPM of the turbine. All meters will include custom rim rotors which incorporate an outer shroud around the rotor assembly.This effectively allows HFC to control the number of pulses (K-factor) that the meter is producing. This customer requires a high number of pulses for each turbine meter.

This feature will assure them of better meter resolution and ultimately better accuracy.

A number of the turbine meters will be used at pressures to 15,000 PSI. To accomplish this, high pressure R-Con flanges are incorporated into the meter design along with a flowmeter housing fabricated with a heavy schedule wall thickness. For example, two of the flowmeters will have housings with an I.D. of approximately 2" and an O.D. of 4". Two additional meters will incorporate housings with I.D's of approximately 5" and O.D.'s of 10". This represents a wall thickness of approximately 2½".

A special "fail safe" design, self-lubricating bearing is also incorporated into the design. This will prevent flowmeter component parts from being pushed downstream,in the event of a catastrophic bearing failure.

We are pleased to represent Hoffer Flow Controls as they provide test support for ongoing projects. The flowmeters supplied for this program are direct relatives of the standard HO Series of turbine flowmeters used for "everyday" applications. If you have a "unique" flow requirement, contact us. Hoffer's expertise in providing flow solutions for the most challenging applications can work for you.



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