Method for predicting pump cavitation performance

Method requires the availability of two sets of appropriate data for each pump to be analyzed. At least one set of the data must provide measurable thermodynamic effects of cavitation

Experimental studies on thermodynamic effects of developed cavitation

A method for predicting thermodynamic effects of cavitation (changes in cavity pressure relative to stream vapor pressure) is presented. The prediction method accounts for changes in liquid, liquid temperature, flow velocity, and body scale. Both theoretical and experimental studies used in formulating the method are discussed. The prediction method provided good agreement between predicted and experimental results for geometrically scaled venturis handling four different liquids of widely diverse physical properties. Use of the method requires geometric similarity of the body and cavitated region and a known reference cavity-pressure depression at one operating condition

Method for prediction of pump cavitation performance for various liquids, liquid temperatures, and rotative speeds

Prediction of cavitation performance of centrifugal pump

A General Correlation of Temperature Profiles Downstream of a Heated-Air Jet Directed Perpendicularly to an Air Stream

An experimental investigation was conducted to determine the temperature profile downstream of a heated-air jet directed perpendicularly to an air stream. The profiles were determined at several positions downstream of the jet as functions of jet density, jet velocity, freestream density, free-stream velocity, jet temperature, and orifice flow coefficient. A method is presented which yields a good approximation of the temperature profile in terms of dimensionless parameters of the flow and geometric conditions

Performance of a highly loaded two stage axial-flow fan

A two-stage axial-flow fan with a tip speed of 1450 ft/sec (442 m/sec) and an overall pressure ratio of 2.8 was designed, built, and tested. At design speed and pressure ratio, the measured flow matched the design value of 184.2 lbm/sec (83.55kg/sec). The adiabatic efficiency at the design operating point was 85.7 percent. The stall margin at design speed was 10 percent. A first-bending-mode flutter of the second-stage rotor blades was encountered near stall at speeds between 77 and 93 percent of design, and also at high pressure ratios at speeds above 105 percent of design. A 5 deg closed reset of the first-stage stator eliminated second-stage flutter for all but a narrow speed range near 90 percent of design

Performance with and without inlet radial distortion of a transonic fan stage designed for reduced loading in the tip region

A transonic compressor stage designed for a reduced loading in the tip region of the rotor blades was tested with and without inlet radial distortion. The rotor was 50 cm in diameter and designed for an operating tip speed of 420 m/sec. Although the rotor blade loading in the tip region was reduced to provide additional operating range, analysis of the data indicates that the flow around the damper appears to be critical and limited the stable operating range of this stage. For all levels of tip and hub radial distortion, there was a large reduction in the rotor stall margin

Performance and boundary-layer evaluation of a sonic inlet

Tests were conducted to determine the boundary layer characteristics and aerodynamic performance of a radial vane sonic inlet with a length/diameter ratio of 1 for several vane configurations. The sonic inlet was designed with a slight wavy wall type of diffuser geometry, which permits operation at high inlet Mach numbers (sufficiently high for good noise suppression) without boundary layer flow separation and with good total pressure recovery. A new method for evaluating the turbulent boundary layer was developed to separate the boundary layer from the inviscid core flow, which is characterized by a total pressure variation from hub to tip, and to determine the experimental boundary layer parameters

Energy as Frequency, Relative Velocity and Lorentz Transformations

In quantum mechanics, energy is associated with frequency for both a particle with rest mass and a photon. In the case of the photon, we try to show that this result follows from special relativity (Lorentz transformation) which in the photon case gives rise to relative velocities. We consider a photon moving along the x axis and bouncing back and forth between two mirrors separated by L and moving to the right with speed v. We argue that Lorentz transformations for photons create the notion of relative velocity because E=|p|c, but there still exists a moving frame with velocity v. As a result, a relationship between the energies of the photon moving to the right and then to the left exists with each energy being multiplied by a respective time= 1/ relative speed. This suggests photon energy representing a frequency. . We also note that relative velocities from the Lorentz transformations are the opposite of those associated with the times the photon spends moving from one mirror to the other.. In other words, the photon moving to the right is associated with 1/c-v, but its time with 1/c-v because it looks as if the photon is moving more slowly when trying to hit a mirror that is moving away from it