Data oscillation resolution of propellant flowmeter used in FASTRAC engine testing

SUMMARYThe Stennis Space Centers" horizontal test facility, Marshal Space Flight Centers'propulsion test article and the X-34 flight vehicle are designed ,, ith V-Cone flowmetersfor measurement of both RP-I and LOX flow rate_,, for Fastrac engine te:,ting. Deltapressure transducer data from these flowmeters are used to calibrate the RP- 1 and LOXmixture ratio in the Fastrac engine. Data from the V-Cone flowmeter delta pressuretransducers have excessive oscillation. The delta pressure oscillations have causedflowrate data fluctuations that interfered with making the accurate readings necessary tocalibrate the RP- 1 and LOX mixture ratio required for Fastrac engine operation.The objective of this report is to document the flowmeter data oscillation problem and themethod used to obtain more reliable flowmeter data.The scope of work covered by this report is the LOX and RP- 1 feedline flowmeters,filters and delta pressure transducer data used to support Fastrac engine testing. Thescope of work includes test configurations conducted on both the horizontal test facility(HTF) and the propulsion test article (PTA- 1) at Stennis Space Center (SCC).The typical oscillation amplitude in the HTF LOX flowmeter data is 2 to 5 PSID at amean differential pressure of 2.5 PSID using a Stellar delta pressure transducer. Theoscillation amplitude in the PTA- 1 LOX flowmeter data is 4 to 7 PSID at a meandifferential pressure of 3.9 PSID using a Stellar delta pressure transducer.A combination of Stellar and Rosemount delta pressure transducers were tested with andwith out snubbers. The most reliable LOX flowmeter data was obtained wile using a typeEA snubber with a Stellar delta pressure transducer. The oscillation amplitude in HTFLOX flowmeter data was reduced to 0.3 PSID at a mean differential pressure of 2.5PSID. The oscillation amplitude in PTA-I LOX flowmeter data was reduced to 0.5 to 2PSID at a mean differential pressure of 4.5 PSID. The sense lines were long enough toensure that GOX (from ambient heat transfer) was at the snubber location.The approximate oscillation amplitude in the HTF RP-1 flowmeter ks from 1 to 2 PSI/) ata mean differential pressure of 2 PSID using a Stellar delta pressure transducer.A turbine flowmeter in conjunction with several configurations of Stellar and Rosemountdelta pressure transducers with different types of snubbers were tested. The most reliableRP- 1 flowmeter data was obtained while using a Rosemount delta pressure transducerwith out a snubber. The oscillation amplitude in HTF RP- 1 flowmeter data was reducedto 0.2 PSID at a mean differential pressure of 1.5 PSID. The oscillation amplitude inPTA- 1 RP- 1 flowmeter data was reduced to 0.2 PSID at a mean differential pressure of3.3 PSID. The PTA-I PR-! flowmeter sense lines were kept horizontal to the flowmetersense line ports to reduce any elevation effects on the delta pressure measurement. TheHTF RP- I flowmeter sense lines were primed with RP- 1 prior to test.