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Holl, J. W.

Publications and source records attributed to Holl, J. W..

10 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1978

Tabulation and summary of thermodynamic effects data for developed cavitation on ogive-nosed bodies

Thermodynamic effects data for developed cavitation on zero and quarter caliber ogives in Freon 113 and water are tabulated and summarized. These data include temperature depression (delta T), flow coefficient (C sub Q), and various geometrical characteristics of the cavity. For the delta T tests, the free-stream temperature varied from 35 C to 95 C in Freon 113 and from 60 C to 125 C in water for a velocity range of 19.5 m/sec to 36.6 m/sec. Two correlations of the delta T data by the entrainment method are presented. These correlations involve different combinations of the Nusselt, Reynolds, Froude, Weber, and Peclet numbers and dimensionless cavity length.

Holl, J. W.↗
NASA NTRS1978

Correlations of thermodynamic effects for developed cavitation

The net positive suction head (NPSH) requirements for a pump are determined by the combined effects of cavitation, fluid properties, pump geometry, and pump operating point. An important part of this determination is the temperature depression (Delta T). Correlations are presented of the temperature depression for various degrees of developed cavitation on venturis and ogives. These correlations, based on a semi-empirical entrainment theory, express Delta T in terms of the dimensionless numbers of Nusselt, Reynolds, Froude, Weber, and Peclet, and dimensionless cavity length (L/D). The Delta T data were obtained in Freon 114, hydrogen and nitrogen for the venturis and in Freon 113 and water for the ogives.

Billet, M. L.↗
NASA NTRS1975

Correlations by the entrainment theory of thermodynamic effects for developed cavitation in venturis and comparisons with ogive data

A semi-empirical entrainment theory was employed to correlate the measured temperature depression, Delta T, in a developed cavity for a venturi. This theory correlates Delta t in terms of the dimensionless numbers of Nusselt, Reynolds, Froude, Weber and Peclet, and dimensionless cavity length, L/D. These correlations are then compared with similar correlations for zero and quarter caliber ogives. In addition, cavitation number data for both limited and developed cavitation in venturis are presented.

Billet, M. L.↗
NASA NTRS1975

Thermodynamic effects on developed cavitation

The results of an investigation of thermodynamic effects are presented. Distributions of temperature and pressure in a developed cavity were measured for zero- and quarter-caliber ogives. A semiempirical entrainment theory was developed to correlate the measured temperature depression in the cavity. This theory correlates the maximum temperature depression expressed in dimensionless form as the Jakob number in terms of the dimensionless numbers of Nusselt, Reynolds, Froude, and Peclet, and dimensionless cavity length, L/D. The results show that in general, the temperature depression increases with L/D and temperature and the cavitation number based on measured cavity pressure is a function of L/D for a given model contour, independent of the thermodynamic effect.

Holl, J. W.↗
NASA NTRS1972

Limited cavitation and the related scale effects problem.

It is indicated that the study of limited cavitation can be divided into two parts, namely, the factors which influence the pressure field, and those which influence the bubble dynamics. Major aspects of cavitation nuclei and bubble dynamics are summarized. An analysis is presented of the effects of velocity, size and fluid properties, including the thermodynamic effect. The effects of turbulence, roughness and polymer additives are presented. These include new data on roughness and estimates of the effects of turbulence and polymer additives on jets. An analysis of nonvaporous cavitation with new data on vortex cavitation is presented. Implications concerning scale effects are given.

Holl, J. W.↗
NASA NTRS1966

Cavitation hysteresis.

Cavitation delay time variation with velocity, size, dissolved air content, liquid tension, flow history and surface characteristics

TIME DELAY↗
NASA NTRS1965

Cavitation hysteresis.

Cavitation delay time variation with velocity, size, dissolved air content, liquid tension, flow history and surface characteristics

TIME DELAY↗