Axial Flow Turbomachines Research Articles

Low Reynolds-Number Experiments in an Axial-Flow Turbomachine

The performance of a single-stage, axial-flow turbomachine was studied experimentally at low Reynolds numbers. The study was made with a turbomachine modeled from a large jet-engine type of axial-flow compressor. Low Reynolds numbers were obtained by using a mixture of glycerine and water as the working fluid. The overall performance was determined over a range of Reynolds numbers RT (based on rotor-tip speed and rotor chord) from 2000 to 150,000. The flow rate at each Reynolds number was varied from near shutoff to the maximum permitted by the turbomachine-tunnel systems. Blade-row characteristics were studied by means of quantitative flow surveys before and after each blade row, and by means of extensive flow-visualization experiments within each blade row. The investigation established that sudden or critical changes in performance do not occur in the type of machine tested, between RT of 150,000 and 20,000. Below 20,000 the performance deteriorated more rapidly. A relatively sharp change in performance occurred between RT of 20,000 and 10,000. The results clarified many of the viscous flow details in each blade row which are associated with the deterioration of performance. These effects were very pronounced at RT of 4000 and below. Consequently, a considerable part of the paper is concerned with results obtained at these lower Reynolds numbers. From the point of view of a designer, information is presented in regard to overall performance, guide-vane turning, and guide-vane and stator total-pressure losses, all as functions of Reynolds number. These results are expected to be indicative of performance in turbomachines similar to the one tested here. Other details are concerned with problems such as wall boundary layers, flow reversal at low flow coefficients, lip-clearance flow, flow patterns near shutoff, and flow comparisons in stators with rotating and stationary hubs.

Research on the Axisymmetric Flow through an Axial-Flow Turbo-Machine : 2nd Report, Axisymmetric Flow at Design Point in Multistage Turbo-Machines of Various Vortex Types

In this report, the author has treated the axisymmetric flow at design point in multistage turbo-machines of various vortex types, such as the constant reaction type and the exponential type, using a similar method to that described in 1st Report. Regarding the axisymmetric flow through an axial-flow turbo-machine, the radial equilibrium theory and the actuator disc theory have been expounded, but the effects of impeller breadth and blade shape have not been considered in these theories. The method described in the present paper takes these effects into account. Numerical examples are shown comparing the results calculated on the basis of the above mentioned theories.

Research on the Axisymmetric Flow through an Axial-Flow Turbo-Machine : 1st Report, On the Flow through a Free Vortex Type Impeller

Regarding the axisymmetric flow through an axial-flow turbo-machine, the radial equilibrium theory and the actuator disc theory have been expounded, in which the effects of impeller breadth and blade shape have not been considered. In this paper a method is presented, in which the above mentioned disadvantages are eliminated. To the axisymmetric flow through a turbo-machine of the free vortex type, the author applies the fundamental partial-differential equations derived from the equations given by Lorenz and Bauersfeld, and the following cases are treated. (1) The flow through an impeller at the off-design point is treated on the assumption that the flow in front of the impeller is a potential one, and numerical examples are shown. (2) The flow through an impeller at the design point is treated on the assumption that the flow in front of the impeller is an inviscid shear flow, and it is shown that the flow in the rear of the impeller has a more uniform axial-velocity distribution.

Research on the Axisymmetric Flow through an Axial-Flow Turbo-Machine : 1st Report, On the Flow through a Free Vortex Type Impeller

Regarding the axisymmetric flow through an axial-flow turbo-machine, the radial equilibrium theory and the actuator disc theory have been expounded, in which the effects of impeller breadth and blade shape have not been considered. In this paper a method is presented, in which the above mentioned disadvantages are eliminated. To the axisymmetric flow through a turbo-machine of the free vortex type, the author applies the fundamental partial-differential equations derived from the equations given by Lorenz and Bauersfeld, and the following cases are treated. (1) The flow through an impeller at the off-design point is treated on the assumption that the flow in front of the impeller is potential one, and numerical examples are shown. (2) The flow through an impeller at the design point is treated on the assumption that the flow in front of the impeller is inviscid shear flow, and it is shown that the flow in the rear of the impeller has a more uniform axial-velocity distribution.

Prediction of Axial-Flow Turbomachine Performance by Blade-Element Methods

The blade-element method has been used effectively in the solution of the design problem for axial-flow turbomachines. A considerable body of data has been acquired to support the use of this system. The method has been applied in the investigation reported in this paper to the performance-prediction problem for blade rows in incompressible and compressible flows. Radial distributions of velocity and fluid properties were determined by numerical solution of the radial equilibrium condition, with radial entropy gradients included by using blade-element losses estimated from available experimental information. The effect of a loss gradient on the predicted performance of a typical axial-flow pump configuration is indicated and, for the case of an axial-flow compressor rotor operating in air, performance predicted is compared with experimentally measured performance.

Research on the Axisymmetric Flow through an Axial-Flow Turbo-Machine : 2nd Report, Axisymmetric Flow at Design Point in Multistage Turbo-Machines of Various Vortex Types

Research on the Axisymmetric Flow through an Axial-Flow Turbo-Machine : 2nd Report, Axisymmetric Flow at Design Point in Multistage Turbo-Machines of Various Vortex Types

Discussion: “Prediction of Axial-Flow Turbomachine Performance by Blade-Element Methods” (Serovy, G. K., and Lysen, J. C., 1963, ASME J. Eng. Power, 85, pp. 1–6)

Discussion: “Prediction of Axial-Flow Turbomachine Performance by Blade-Element Methods” (Serovy, G. K., and Lysen, J. C., 1963, ASME J. Eng. Power, 85, pp. 1–6)

Discussion: “Prediction of Axial-Flow Turbomachine Performance by Blade-Element Methods” (Serovy, G. K., and Lysen, J. C., 1963, ASME J. Eng. Power, 85, pp. 1–6)

Discussion: “Prediction of Axial-Flow Turbomachine Performance by Blade-Element Methods” (Serovy, G. K., and Lysen, J. C., 1963, ASME J. Eng. Power, 85, pp. 1–6)

Discussion: “Prediction of Axial-Flow Turbomachine Performance by Blade-Element Methods” (Serovy, G. K., and Lysen, J. C., 1963, ASME J. Eng. Power, 85, pp. 1–6)

Discussion: “Prediction of Axial-Flow Turbomachine Performance by Blade-Element Methods” (Serovy, G. K., and Lysen, J. C., 1963, ASME J. Eng. Power, 85, pp. 1–6)

Closure to “Discussions of ‘Prediction of Axial-Flow Turbomachine Performance by Blade-Element Methods’” (1963, ASME J. Eng. Power, 85, pp. 6–7)

Closure to “Discussions of ‘Prediction of Axial-Flow Turbomachine Performance by Blade-Element Methods’” (1963, ASME J. Eng. Power, 85, pp. 6–7)

Discussion: “Prediction of Axial-Flow Turbomachine Performance by Blade-Element Methods” (Serovy, G. K., and Lysen, J. C., 1963, ASME J. Eng. Power, 85, pp. 1–6)

Discussion: “Prediction of Axial-Flow Turbomachine Performance by Blade-Element Methods” (Serovy, G. K., and Lysen, J. C., 1963, ASME J. Eng. Power, 85, pp. 1–6)

An Experimental Arrangement for the Measurement of the Pressure Distribution on High-Speed Rotating Blade Rows

Abstract For several years past the research staff of the Institute for Turbomachines of the Aachen Technical University has carried out measurements on rotating turbine blading. This program is part of a comprehensive effort directed toward the experimental investigation of the three-dimensional flow through axial-flow turbomachines.

Analysis of Viscous Laminar Incompressible Flow Through Axial-Flow Turbomachines With Infinitesimal Blade Spacing

Abstract The Lorenz theory has been extended to the viscous, laminar, incompressible flow through axial-flow turbo-machines with infinitesimal blade spacing. Expressions are derived for the velocity components, pressure, power input and output for arbitrary blade surfaces. A numerical example is presented and the flow variables and blade surfaces are plotted.

Latticed Wing of invariable Outflow Direction : 12th Report of Study of Axial-flow Turbo-machine

Calculating the latticed wing of small pitch-chord ratio, it is observed that its outflow direction is scarcely affected by its inflow direction. This tendency seems to increase with the increase of the ratio of passage length to width, rather than the pitch-chord ratio itself. Does only the ratio of passage length to width affect to this fact, or will other wing shapes affect, too? It must be examined. With this intention, I have inquired into the potential theory of small pitch latticed wing, and reached the following conclusions : It is noticed that the outflow direction of latticed wing become : invariable rapidly by reducing its pitch, and not only the ratio of passage length to width, but the inflow angle and outflow angle affect to this character.

The Mean Flow in Kaplan Turbines

Abstract All theories now in use for the design of the bladings of Kaplan turbines and pumps are based on the assumptions that the fluid moves on concentric cylinders and that no trailing vorticity is shed off the blading. Approximate corrections are here found arising from the fact that the flow does not, in practice, satisfy these assumptions. These corrections are the more important the smaller the ratio of hub diameter to tip diameter. An approximation to them is found from investigation of the axially symmetrical mean flow in the rotor, which is obtained when the velocity components at any point are replaced by their mean values with respect to the angular co-ordinate. This approximation is the more accurate the smaller the pitch-chord ratio. It is found that the three-dimensional effects in the flow are due to the transverse component of the vorticity (“ring vorticity”). Formulas for the velocity components induced by it are given. Two distinct problems arise in connection with the design of a Kaplan blading, viz., (a) to find the shape of the blade and the pressure distribution for a prescribed load distribution, under the optimum working condition, and (b) to find the performance and pressure distribution for a prescribed blade shape, after a change of pitch. The theory applies also to multistage axial-flow turbomachines where the mean velocity is not too high for knowledge of the incompressible flow to be of interest.