Fluid reaction surfaces (i.e. – impellers) – Rotor having flow confining or deflecting web – shroud or... – Radially extending web or end plate
Patent
1995-02-01
1997-11-11
Kwon, John T.
Fluid reaction surfaces (i.e., impellers)
Rotor having flow confining or deflecting web, shroud or...
Radially extending web or end plate
416223B, F04D 2938
Patent
active
056856962
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to a turbomachine including a centrifugal pump or a mixed flow pump for pumping liquid, a blower or a compressor for compression of gas, and more particularly to a turbomachine having an impeller which has a fluid dynamically improved blade profile for suppressing a meridional component of secondary flow.
Conventionally, in flow passages of an impeller in a centrifugal or a mixed flow turbomachine, main flows flowing along flow passages are affected by secondary flow generated by movement of low energy fluid in boundary layers on wall surfaces due to static pressure gradients in the flow passages. This phenomenon leads to the formation of streamwise vortices or flow having non-uniform velocity in the flow passage, which in turn results in a substantial fluid energy loss not only in the impeller but also in the diffuser or guide vanes downstream of the impeller.
The secondary flow is defined as flow which has a velocity component perpendicular to the main flow. The total energy loss caused by the secondary flows is referred to as the secondary flow loss. The low energy fluid accumulated at a certain region in the flow passage may cause flow separation on a large scale, thus producing a positively sloped characteristic curve and hence preventing the stable operation of the turbomachine.
There are two known approaches for suppressing the secondary flows in a turbomachine, one of which is to make the impeller have a specific flow passage geometry, the other of which is to supply energy from the outside. As an example of the former approach using a specific flow passage geometry, there is a known method in which blades of the impeller in an axial turbomachine are leaned towards the circumferential direction thereof or the direction of the suction or discharge side (L. H. Smith and H. Yeh, "Sweep and Dihedral Effects in Axial Flow Turbomachinery", Trans ASME, Journal of Basic Engineering, Vol. 85, No. 3, 1963, pp. 401-416), a method in which a radial rotor has a blade curvature in the spanwise direction with a convex blade pressure surface and/or a concave blade suction surface(GB2224083A), or a method in which blades in a turbine cascade are leaned or curved toward a circumferential direction thereof (W. Zhongqi, et al., "An Experimental Investigation into the Reasons of Reducing Secondary Flow Losses by Using Leaned Blades in Rectangular Turbine Cascades with Incidence Angle", ASME Paper 88-GT-4). These methods are known to have a favorable influence upon the secondary flows in the cascade if applied appropriately.
However, since the influence of the profile of a blade camber line or a blade cross-section upon the secondary flow has not been essentially known, the effect of blade lean or spanwise blade curvature is utilized under a certain limitation without changing the blade camber line or the blade cross-section substantially. Further, Japanese laid-open Patent Publication No. 63-10281 discloses a structure in which a projecting portion is provided at the corner of a hub surface and a blade surface in a turbomachine to reduce the secondary flow loss. Since such flow passage profile is a specific blade profile having a nonaxisymmetric hub surface, it is difficult to manufacture the impeller.
In all cases of the above prior arrangements, a method of achieving the effect universally has not been sufficiently studied.
Therefore, universal methods of suppressing the secondary flows under different design conditions and for the different types of turbomachines have not been established. Under these circumstances, there are many cases that the above effect is reduced, or to make matters worse, undesirable effects are obtained. As a result, as of now, there is no standard design criterion for reducing secondary flow by using specific flow passage geometry. Thus the three-dimensional geometry of the impeller has been designed by trial and error to find the optimum profile of the impeller for suppressing secondary flow.
As an example of the latter approach, i
REFERENCES:
patent: 3028140 (1962-04-01), Lage
patent: 4465433 (1984-08-01), Bischoff
patent: 5112195 (1992-05-01), Cox
patent: 5458457 (1995-10-01), Goto et al.
Smith et al., "Sweep and Dihedral Effects in Axial-Flow Turbomachinery", Journal of Basic Engineering, vol. 85, No. 3, Sep. 1963, pp. 401-416.
Zhongi et al., "An Experimental Investigation Into the Reasons of Reducing Secondary Flow Losses by Using Leaned Blades in Rectangular Turbine Cascades with Incidence Angle", ASME Paper 88-GT-4, pp. 1-7 (presented Jun. 1988).
Biesinger et al., "Reduction in Secondary Flows and Losses in a Turbine Cascade by Upstream Boundary Layer Blowing", ASME Paper 93-GT-114, pp. 1-16 (presented May 1993).
Zangeney, "A Compressible Three-Dimensional Design Method for Radial and Mixed Flow Turbomachinery Blades", International Journal of Numerical Methods of Fluids, vol. 13, pp. 599-624, 1991.
Borges, "A Three-Dimensional Inverse Method for Turbomachinery: Part I-Theory", ASME, Journal of Turbomachinery, vol. 112, pp. 346-354, Jul. 1990.
Yang et al., "Aerodynamic Design of Turbomachinery Blading in Three-Dimensional Flow: An Application to Radial Inflow Turbines", ASME Paper 92-GT-74, pp. 1-13 (presented Jun. 1992).
Dang, "A Fully Three-Dimensional Inverse Method for Turbomachinery Blading in Transonic Flows", ASME, Journal of Turbomachinery, vol. 115, pp. 354-361, Apr. 1993.
Dawes, "Development of a 3D Navier Stokes Solver for Application to all Types of Turbomachinery", ASME Paper 88-GT-70, pp. 1-11 (presented Jun. 1988).
Stepanoff, "Centrifugal and Axial Flow Pumps", John Wiley & Sons, Inc. New York, 1957, pp. 94-105.
Dicmas, "Vertical Turbine, Mixed Flow, and Propeller Pumps", MacGraw-Hill, New York, pp. 305-311, 1962.
Borges, "A Proposed Through-Flow Inverse Method for the Design of Mixed-Flow Pumps", International Journal of Numerical Methods in Fluids, vol. 17, Dec. 1993, pp. 1097-1114.
Zangeneh et al., "A Fully Compressible Three Dimensional Inverse Design Method Applicable to Radial and Mixed Flow Turbomachines", ASME Paper 90-GT-198, pp. 1-9 (presented Jun. 1990).
Zangeneh, "Three Dimensional Design of a High Speed Radial-Inflow Turbine by a Novel Design Method", ASME Paper 90-GT-235, pp. 1-8 (presented Jun. 1990).
Zangeney, "Inviscid-Viscous Interaction Method for 3D Inverse Design of Centrifugal Impellers", ASME Paper 93-GT-103, pp. 1-10 (presented May 1993).
Goto et al., "Internal Flow Fields in a Mixed-Flow Impeller Designed by Three-Dimensional Inverse Method", The Lecture of the 30th General Meeting in the Association of Turbomachinery, May 1994.
Goto Akira
Harada Hideomi
Zangeneh Mehrdad
Ebara Corporation
Ebara Research Co. Ltd.
Kwon John T.
University College London
LandOfFree
Centrifugal or mixed flow turbomachines does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Centrifugal or mixed flow turbomachines, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Centrifugal or mixed flow turbomachines will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1224121