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At least 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

An automated secondary standard for calibrating liquid flowmeters

A secondary working standard of flow calibration has been developed to be used in place of a primary weight-time standard, and which can thereby effect a 75 percent reduction in calibration time while maintaining acceptable accuracies. The secondary standard uses six previously calibrated turbine-type flowmeters built into two manifold systems containing automatically switched flow valves. The pair of systems is capable of covering the flow range of 0.0004 to 19 1/s (0.007 to 300 gpm) with the uncertainty in volume flow rate not exceeding plus or minus 0.25 percent over the range 0.06 to 19 1/s and not exceeding plus or minus 0.5 percent over the range 0.0004 to 0.06 1/s. Data reduction and plotting of results are by computer.

Hobart, H. F.↗
NASA NTRS1981

Fast calibration of gas flowmeters

Digital unit automates calibration sequence using calculator IC and programmable read-only memory to solve calibration equations. Infrared sensors start and stop calibration sequence. Instrument calibrates mass flowmeters or rotameters where flow measurement is based on mass or volume. This automatic control reduces operator time by 80 percent. Solid-state components are very reliable, and digital character allows system accuracy to be determined primarily by accuracy of transducers.

Lisle, R. V.↗
NASA NTRS1981

Evaluation of several ultrasonic flowmeter transducers in cryogenic environment

Eighteen piezoelectric ultrasonic flowmeter transducers were laboratory tested to determine their suitability and long range reliability for use by the National Transonic Facility (NTF) to measure the flow rate of 450 Kg/sec of liquid nitrogen (LN2). Tests included thermally cycling each transducer 50 to 150 times over a temperature range of 295 K (ambient) to 77 K (LN2). The transducers were submerged in liquid nitrogen for 1 to 4 hours and the signal strength and quality noted. Results disclose that the current state-of-the-art ultrasonic flow transducers are very reliable and will meet the stringent requirements of the NTF.

Moughon, W. C.↗
NASA NTRS1986

Flowmeter for Clear Fluids

Electronic flowmeter measures flow rate of clear or translucent fluids. Instrument produces electrical signal proportional to volume of fluid flowing through it per unit time. Optoelectronic instrument generates electrical signal proportional to fluid-flow rate.

White, P. R.↗
NASA NTRS1985

Vortex shedding flowmeters for liquids at high flow velocities

A number of vortex shedding flowmeter designs for flow measurements in liquid oxygen ducts on the space shuttle main engines have been tested in a high head water flow test facility. The results have shown that a vortex shedding element or vane spanning the duct can give a linear response to an average flow velocity of 46 m/s (150 ft/s) in a 1 1/2 inch nominal (41 mm actual) diameter duct while a vane partially spanning the duct can give a linear response to velocities exceeding 55 m/s (180 ft/s). The maximum pressure drops across the flow sensing elements extrapolate to less than 0.7 MPa (100 psi) at 56 m/s (184 ft/s) for liquid oxygen. The test results indicate that the vanes probably cannot be scaled up with pipe size, at least not linearly.

Siegwarth, J. D.↗
NASA NTRS1987

Reducing Fatigue in a Rotary Flowmeter

Redesign of vanes straightening flow of liquid in rotary flowmeter increase fatigue lives of vanes and rotor. Purpose of vanes to eliminate turbulence so proportionality between flow and rotor speed constant. Nonuniform but symmetrical, new spacing of straightener vanes prevents flow wake from strongly interacting with rotor blades. At same time, vanes ensure accurate flow-rate measurement.

Rao, G.↗
NASA NTRS1988

Pressure drop and temperature rise in He II flow in round tubes, Venturi flowmeters and valves

Pressure drops in highly turbulent He II flow were measured in round tubes, valves, and Venturi flowmeters. Results are in good agreement with single-phase flow correlations for classical fluids. The temperature rise in flow in a round tube was measured, and found to agree well with predictions for isenthalpic expansion. Cavitation was observed in the venturis under conditions of low back pressure and high flow rate. Metastable superheating of the helium at the venturi throat was observed before the helium made a transition to saturation pressure.

Walstrom, P. L.↗
NASA NTRS1989

Low flow vortex shedding flowmeter

The purpose was to continue a development project on a no moving parts vortex shedding flowmeter used for flow measurement of hypergols. The project involved the design and construction of a test loop to evaluate the meter for flow of Freon which simulates the hypergol fluids. Results were obtained on the output frequency characteristics of the flow meter as a function of flow rate. A family of flow meters for larger size lines and ranges of flow was sized based on the results of the tested meter.

Waugaman, Charles J.↗
NASA NTRS1965

Electromagnetic flowmeter.

Transducer and electronic detector of electromagnetic flow meter for volumetric flow measurement for both electrically conducting and dielectric fluids

FLOW METER↗
NASA NTRS1966

Laser Doppler flowmeter measures gas velocity

Utilizing the large magnitudes of Doppler shifts obtainable from a CW gas laser, local velocity vectors are measured by using the visible light from the laser. This technique is applicable for the measurement of velocity of any moving surface.

Foreman, W.↗