Cryogenic fluid damper seals operating close to the liquid-vapor region (near the critical point or slightly sub-cooled) are likely to develop a two-phase flow region which affects the seal performance and reliability. An all-liquid, liquid-vapor, and all-vapor, i.e., a “continuous vaporization” bulk flow model for prediction of the seal dynamic forced response is given in Part I. The numerical method of solution of the flow equations is detailed here. Computed predictions for static seal characteristics, leakage and axial pressure drop, correlate well with existing measurements for a gaseous nitrogen seal and a liquid nitrogen seal with two-phase at the seal exit plane. The effects of two-phase flow regimes on the dynamic force coefficients and stability of an oxygen damper seal are discussed. Fluid compressibility effects, particularly for mixtures with low mass content of vapor, are of utmost importance. Under these conditions, an increase on seal direct stiffness and reduction of whirl frequency ratio are shown to occur.

1.
Arauz, G., 1997, “Analysis of Two-Phase Flow in Damper Seals for Cryogenic Turbomachinery,” Ph.D. dissertation, Mechanical Engineering Dept., Texas A&M University, May.
2.
Arauz, G., and San Andres, L., 1998, “Analysis of Two-Phase Flow in Cryogenic Damper Seals. Part I: Theoretical Model,” ASME JOURNAL OF TRIBOLOGY, published in this issue pp. 221–227.
3.
Beatty
P. A.
, and
Hughes
W. F.
,
1987
, “
Turbulent Two-Phase Flow in Annular Seals
,”
ASLE Transactions
, Vol.
30
, pp.
11
18
.
4.
Hendricks, R. C., 1987, “Straight Cylindrical Seals for High Performance Turbomachinery,” NASA TP-1850.
5.
Hendricks, R. C., Braun, M. J., and Mullen, R. L., 1987, “Two-Phase Flows and Heat Transfer Within Systems with Ambient Pressure Above the Thermodynamic Critical Pressure,” NASA TM-87228.
6.
Iwatsubo, T., and Nishino, T., 1993, “An Experimental Study on the Static and Dynamic Characteristics of Pump Annular Seals,” 7th Workshop on Rotordynamic Instability Problems in High Performance Turbomachinery, held at Texas A&M University, College Station, Texas, May 10–12.
7.
McCarty, R. D., NBS Standard Reference Data Base 12, 1986, “Thermophysical Properties of Fluids, MIPROPS-86,” Thermophysics Division, Center for Chemical Engineering, National Bureau of Standards, Colorado.
8.
San Andres
L.
,
1992
, “
Analysis of Turbulent Hydrostatic Bearings with a Barotropic Cryogenic Fluid
,”
ASME JOURNAL OF TRIBOLOGY
, Vol.
114
, pp.
755
765
.
9.
San Andres
L.
1996
, “
Angled Injection-Hydrostatic Bearings Analysis and Comparisons to Test Results
,”
ASME JOURNAL OF TRIBOLOGY
, Vol.
119
, Jan., p.
179
179
.
10.
Van Doormal
J. P.
, and
Raithby
D.
,
1984
, “
Enhancements of the SIMPLE Method for Predicting Incompressible Fluid Flows
,”
Numerical Heat Transfer
, Vol.
7
, pp.
144
163
.
11.
Yang, Z., 1992, “Thermohydrodynamic Analysis of Product-Lubricated Hydrostatic Bearings in Turbulent Regime,” Ph.D dissertation, Mechanical Engineering Dept., Texas A&M University.
12.
Yang
Z.
,
San Andres
L.
,
Childs
D.
,
1993
, “
Thermal Effects in Cryogenic Liquid Annular Seals—Part I: Theory and Approximate Solution. Part II: Numerical Solution and Results
,”
ASME JOURNAL OF TRIBOLOGY
, Vol.
115
, pp.
277
284
.
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