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Rostafinski, W.

Publications and source records attributed to Rostafinski, W..

17 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1992

Detonation duct gas generator demonstration program

An experimental demonstration is presented for the generation of detonation waves that move periodically across high speed channel flow; these waves can compress the outflow from a low pressure compressor, and thereby both reduce the compressor requirements associated with conventional gas turbines and enhance thermodynamic efficiency through isochoric energy addition. By generating transient transverse waves, rather than standing waves, shock-wave losses are reduced by an order of magnitude; the result is a Humphrey cycle augmenting the basic Brayton-cycle gas turbine. Attention is presently given to results from an experimental detonation duct.

Wortman, A.↗
NASA NTRS1986

Analysis of fully stalled compressor

An analysis yields a model for energy transfer in compressor stages operating in the closed-throttle condition. The derivation indicates that three geometry parameters (hub/tip ratio, aspect ratio, and rotor blade setting angle) influence the values of pressure coefficient when the compressor flow is close to zero.

Rostafinski, W.↗
NASA NTRS1986

Analysis of fully stalled compressor

An analysis yields a model for energy transfer in compressor stages operating in the closed-throttle condition. The derivation indicates that three geometry parameters (hub/tip ration, aspect ration, and rotor blade setting angle) influence the values of pressure coefficient when the compressor flow is close to zero.

Rostafinski, W.↗
NASA NTRS1981

On the propagation of long waves in acoustically treated, curved ducts

A two-dimensional, detailed study is presented on the behavior of long waves in lined, curved ducts. The analysis includes a comparison between the propagation in curved and straight lined ducts. A parametric study was conducted over a range of wall admittance and duct wall separation. The complex eigenvalues of the characteristic equation, which in the case of a curved duct are also the angular wavenumbers, have been obtained by successive approximations.

Rostafinski, W.↗
NASA NTRS1981

On the propagation of long waves in acoustically treated, curved ducts

A two dimensional study is presented on the behavior of long waves in lined, curved ducts. The analysis includes a comparison between the propagation in curved and straight lined ducts. A parametric study was conducted over a range of wall admittance and duct wall separation. The complex eigenvalues of the characteristic equation, which in the case of a curved duct are also the angular wavenumbers, were obtained by successive approximations.

Rostafinski, W.↗
NASA NTRS1975

Acoustic systems containing curved duct sections

The analysis of waves in bends in acoustical ducting of rectangular cross section is extended to the study of motion near discontinuities. This includes determination of the characteristics of the tangential and radial components of the non-propagating modes. It is established that attenuation of the non-propagating modes strongly depends on frequency and that, in general, the sharper the bend, the less attenuation may be expected. Evaluation of a bend's impedance and of impedance-generated reflections is also presented in detail.

Rostafinski, W.↗
NASA NTRS1975

Acoustic systems containing curved duct sections

The analysis of waves in bends in acoustical ducting of rectangular cross section was extended to the study of motion near discontinuities. This included determination of the characteristics of the tangential and radial components of the nonpropagating modes. It is established that attenuation of the nonpropagating modes strongly depends on frequency and that, in general, the sharper the bend, the less attenuation may be expected. Evaluation of a bend's impedance and of impedance-generated reflections is also presented in detail.

Rostafinski, W.↗
NASA NTRS1974

Transmission of wave energy in curved ducts

Investigation of the ability of circular bends to transmit acoustic energy flux. A formulation of wave-energy flow is developed for motion in curved ducts. A parametric study over a range of frequencies shows the ability of circular bends to transmit energy in the case of perfectly rigid walls.

Rostafinski, W.↗
NASA NTRS1974

Analysis of propagation of waves of acoustic frequencies in curved ducts

The propagation of waves of acoustic frequencies in curved ducts of rectangular cross section is studied for the first four modes. The analysis makes use of Bessel functions of the order (n + 1/2) to construct curves of wavenumber in the duct versus imposed wavenumber and to determine the profile of vibrational velocities. A wide range of duct widths and unrestricted radii of curvature have been considered. The characteristics of motion in a bend are compared with propagation of waves in a straight duct, and important differences in the behavior of waves are noted.

Rostafinski, W.↗
NASA NTRS1973

Propagation of waves of acoustic frequencies in curved ducts

The propagation of waves of acoustic frequencies in curved ducts is studied for the first four modes. The analysis makes use of Bessel functions to construct curves of wave number in the duct versus imposed wave number. The results apply to ducts of arbitrary width and arbitrary radii of curvature. The characteristics of motion in a bend are compared with propagation of waves in a straight duct, and important differences in the behavior of waves are noted.

Rostafinski, W.↗
NASA NTRS1973

Transmission of wave energy in curved ducts

A formation of wave energy flow was developed for motion in curved ducts. A parametric study over a range of frequencies determined the ability of circular bends to transmit energy for the case of perfectly rigid walls.

Rostafinski, W.↗
NASA NTRS1972

On propagation of long waves in curved ducts.

A two-dimensional detailed study of the behavior of long waves in curved ducts and in junctions between straight and curved ducts will be given. The mathematical treatment of the problem utilizes the method of separation variables. Solutions and expressions for principal mode of the wave are obtained by using the linearized equation of motion solved for its characteristic values. The unavoidable approximations in the numerical solutions of the cylindrical functions are due to use of series expansion of Bessel functions and from restrictions necessary to solve infinite matrices.

Rostafinski, W.↗
NASA NTRS1971

On propagation of long waves in curved ducts.

Propagation of waves in curved ducts and pipes belong to the class of motion which is characterized by wave patterns totally different from those known in straight ducts or in unlimited space. The curvilinear boundaries are responsible for the appearance of a continuous standing radial wave which in turn affects the transmitted tangential waves. The purpose of this paper is to solve the problem of propagation of long acoustic waves in slightly and sharply bent ducts. This problem has been only partially analyzed by various authors. In this study two acoustic systems are considered which allow determination of the basic modes of motion and describe the transition and distortion of plane waves as they propagate down the curved channel. A detailed study of the behavior of waves in junctions between straight and curved ducts is also given. Solutions and expressions for principal modes of the wave are obtained by using the linearized equation of motion solved for its characteristic values. This original approach required a novel use of Bessel functions to determine the characteristic values of the steady and the decaying fields of motion.

Rostafinski, W.↗
NASA NTRS1971

On propagation of long waves in curved ducts

Long acoustic wave propagation in curved ducts and junctions between straight and curved ducts utilizing Bessel functions for steady and decaying fields of motion

Rostafinski, W.↗
NASA NTRS1970

Propagation of long waves in curved ducts

Mathematical model for two-dimensional, long-wave propagation in curved acoustic ducts determining vibrational velocity distribution and variation and phase of motion at any point in system

Rostafinski, W.↗
NASA NTRS1969

Prediction of performance of centrifugal pumps during starts under pressure

Method which calculates start-up characteristics of centrifugal pumps reveals a capacity to predict pressure drop characteristics of pumps with vaned diffusers. Calculations are based on pump geometry, design-point flow, speed, and pressure rise, and the pump characteristic within range of approximately ten percent of the design-point flow.

Rostafinski, W.↗