Mixed Flow Turbine Research Articles

Closure to “Discussion of ‘Computer Aided Design of Mixed Flow Turbines for Turbochargers’” (1979, ASME J. Eng. Power, 101, pp. 448–449)

Closure to “Discussion of ‘Computer Aided Design of Mixed Flow Turbines for Turbochargers’” (1979, ASME J. Eng. Power, 101, pp. 448–449)

Expulsion of water from the turbine runner on switching a turbo-generator to a synchronous condenser regime

1. The fastest and most complete possible expulsion of water from the turbine runner is a necessary condition for switching a unit to the SC regime. 2. The water should be expelled by compressed air. The pneumatic systems of hydroelectric stations intended for this purpose are designed for an initial pressure of 8 and 40 atm. 3. The air collectors should consist of large-diameter pipes placed inside the powerhouse along one of the galleries of generator room. 4. For delivery of compressed air to the runner pit it is recommended to use a slide valve with a hydraulic drive at a pressure of 8 atm and plug cock with a servomotor at a pressure of 40 atm. 5. For automatic monitoring and maintenance of the level of expelled water in the draft tube it is recommended to use a DRP level regulator, produced by “Soyuzenergoavtomatika,” or the ORGRES level-regulating float relay. 6. The existing design of valves admitting atmospheric air under the runner which are installed on the hollow shaft of mixed-flow turbines do not meet the operating requirements of the unit in the active and SC regimes. 7. In the case of switching high-head units with low-speed turbines to the SC regime it is necessary to expel the water from the spiral casing as well was from the runner pit, since only in this case is complete expulsion achieved.

Derivation of Global Parametric Performance of Mixed Flow Hydraulic Turbine Using CFD

The testing of physical turbine models is costly, time consuming and subject to limitations of laboratory setup to meet International Electro technical Commission (IEC) standards. Computational fluid dynamics (CFD) has emerged as a powerful tool for funding numerical solutions of wide range of flow equations whose analytical solutions are not feasible. CFD also minimizes the requirement of model testing. The present work deals with simulation of 3D flow in mixed flow (Francis) turbine passage; i.e., stay vane, guide vane, runner and draft tube using ANSYS CFX 10 software for study of flow pattern within turbine space and computation of various losses and efficiency at different operating regimes. The computed values and variation of performance parameters are found to bear close comparison with experimental results.Key words: Hydraulic turbine; Performance; Computational fluid dynamics; Efficiency; LossesDOI: 10.3126/hn.v7i0.4239Hydro Nepal Journal of Water, Energy and EnvironmentVol. 7, July, 2010Page: 60-64Uploaded date: 31 January, 2011

Paper 7: Control of Variable-Discharge Pumps and Dangers of Pipeline Resonance

The discharge and power input of Deriaz mixed-flow pumps and pump turbines can be controlled over a wide range without significant loss in efficiency by movement of the blades. The attainment of the highest pump efficiency involves a small region of positive slope in the head discharge graph.This paper examines the limitations of designing pumps which do not exhibit positive slope and the problems of governing if a positive-slope region is accepted.It is shown that operation in the positive-slope region can introduce a serious organ-pipe resonant instability in the pipeline.A simple criterion to determine whether or not such oscillations will occur is given. This stability criterion involves the dynamic characteristics of both the pump and the pipeline.Finally, computer studies of a particular Deriaz pump installation are presented. These underline the severity of the situation should resonance develop and show how it can be avoided by the use of an air bottle of appropriate design.

On a Theory of Radial-Flow Gas Turbine : 2nd Report, Mixed-Flow Turbine

In the 1st report radial-inflow turbines of purely radial-flow type were investigated. in this report, in order to introduce design data and to explain various performances of radial-inflow turbines of mixed-flow type, by investigating relations between the isentropic heat drop in the impeller and the distribution of the static pressure at the outlet of the impeller, a general formula of efficiency was introduced adopting such parameters as used in the 1st report. The characteristics of radial turbines of mixed-flow type, when the ratio of the diameter at the outlet of the impeller to the outer diameter of the impeller was about 0.6, were calculated and effects of several factors on efficiency were investigated. Then a radial turbine of mixed-flow type was designed for supercharging diesel-engines and the velocity diagram and the dimensions of the designed rotor were shown.

The Flow Through Centrifugal Compressors and Pumps

Abstract The flow through centrifugal compressors and pumps is a three-dimensional flow problem and is of such a complex nature that an exact solution is not obtainable. The literature (1, 2) shows the differential equations which the flow through an impeller must follow. An approximate solution to these equations is found by means of certain assumptions which are possible for impellers within a limited range of specific speeds. The solution gives the approximate velocity and pressure distribution in the impeller passages. The knowledge of the velocity distribution is used to analyze the phenomena of pulsation and blade stalling. The method has also been used in mixed-flow compressors and radial- and mixed-flow turbines. The application of this method for two impellers and test data are presented.

The American Mixed-Flow Turbine and Its Setting

The Proprietors of the Locks and Canals on Merrimack River were incorporated in 1792 for the purpose of making the stream navigable from tidewater to the New Hampshire line. The development of the water power available at the Pawtucket Falls, in Lowell, Mass., was commenced by the Proprietors in 1821, and since that time this power has been utilized in increasing amounts by the almost continuous addition of new and improved water-wheels.

Discussion of “The American Mixed-Flow Turbine”

Discussion of “The American Mixed-Flow Turbine”

Closure to “The American Mixed-Flow Turbine”

Closure to “The American Mixed-Flow Turbine”