TWO-PHASE PRESSURE LOSSES. Quarterly Progress Report No. 3, August 12- November 12, 1962

Technical Report · Wed Dec 12 04:00:00 EST 1962

OSTI ID:4721262

Janssen, E; Kervinen, J A

The pressure drop along a 0.5-in. x 1.75-in. channel in the horizontal and in the vertical, flow up and flow down, orientations were measured under single and two-phase flow conditions at 600, 1000, and 1400 psia. The flow was varied from 0.25 x 10/sup 6/ to 2.0 x 10/sup 6/ lb/hr-ft/sup 2/, and the quality from zero to 95 per cent. The pressure drop across four different contraction- expansion geometries was also measured under single and two-phase flow conditions. The two-phase pressure drop results for the straight channel at 1000 psia and for three of the contraction-expansion geometries under single phase flow are reported. The pressure drop curves for the straight channel in three orientntions, all at the same flow, tend to converge as the quality is increased. This is due to the decreasing magnitude of the hydrostatic term with increasing quality. Larson's data were used to evaluate the hydrostatic term, and from this a frictional loss was calculated for all three orientations. Agreement between the three orientations is good as high flows, and at low flows and high qualities. It is poor at low flows and low qualities. Poor agreement means that either the friction loss is not independent of the direction of flow or that Larson's data are not applicable, or both. The horizontal pressure drop data were used to evalante the friction loss for the vertical cases, and from this, the void fraction alpha was calculated for both fiow up and flow down. alpha for flow up at the lower flow conditions (0.5 x 10/sup 6/ and 1 x 10/sup 6/ lb/hr-ft/sup 2/ ) is in good agreement with Larson's results except nt the higher qualities. At the high flow condition (2 x 10/sup 6/ lb/hr-ft/sup 2/), alpha is in relatively good agreement with the homogeneous model. alpha for flow down at 0.5 x 10/sup 6/ lb/hr-ft/sup 2/ lies in the band 0.85 < alpha < 0.92 for qualities from 10 to 74 per cent. At the high flow condition, alpha appears to be in fair agreemert with Larson's curve. The single phase loss coefficient for the three expansion-expansion geometries is plotted versus channel Reynolds number. High speed movies were taken of twophase flow in both the straight channel and with one of the expansion-contraction geometries, nt selected conditions of flow and quality. With the straight channel horizontal, G = 1 x 10/sup 6/ lb/hr-ft/sup 2/ , asymmetry was observed in the flow pattern at 20 per cent quality, and strong stratification at 5 per cent quality. With the contraction-expansion insert installed, flow vertical, G = 1 x 10/sup 6/ lb/hr-ft/sup 2/, 5 per cent quality, a jet was observed in the region past the insert with strong mixing action along the jet boundaries. The two-phase mixture in and past the insert had a finely homogenized appearance. Because of difference in character of horizontal flow compared with vertical flow, particularly at low flows and qualities, the frictional pressure loss may be quite different. The need for quantitative measurement of voids in the flow up and flow down cases is clearly indicated. (auth)

• Research Organization: General Electric Co. Atomic Power Equipment Dept., San Jose, Calif.
• NSA Number: NSA-17-010792
• OSTI ID: 4721262
• Report Number(s): GEAP-4148
• Country of Publication: United States
• Language: English

Related Subjects

CONFIGURATION
DIAGRAMS
ENGINEERING AND EQUIPMENT
EVAPORATION
EXPANSION
FLOW MODELS
FLUID FLOW
FRICTION
JETS
LIQUIDS
LOSSES
MASS
MATHEMATICS
MEASURED VALUES
MIXING
PERFORMANCE
PHOTOGRAPHY
PRESSURE
QUANTITY RATIO
REYNOLDS NUMBER
STANDARDS
TUBES
TURBULENCE
VAPORS
VELOCITY
VOID FRACTION