Abstract: Disclosed is an impeller for a turbomachine. The impeller comprises a hub, full blades equidistantly disposed on the hub in a circumferential direction, and a splitter blade disposed between each adjacent two of the full blades. The splitter blade is shaped in such a way that a spanwise distribution of a pitchwise position of a leading edge of the splitter blade is determined according to a spanwise and pitchwise non-uniformity distribution of fluid velocity of a fluid flowing into the splitter blade, whereby a non-dimensional circumferential position of a leading edge of the splitter blade varies in a spanwise direction.

Abstract: A turbine nozzle comprises an array of nozzle blades (1) U disposed circumferentially in an annular passage (4) defined between inner and outer rings of a diaphragm and fixed to the inner and outer rings of the turbine diaphragm. The flow passage is defined between a pressure surface (F) and a suction surface (B) of adjacent ones of the nozzle blades, and a cross section of the flow passage includes predetermined ranges extending along a blade height (h) from the inner and outer diameter surfaces (hub and tip end walls) and defined by a curved line, and another range defined by a substantially straight line.

Abstract: A turbine device includes a rotor having a plurality of turbine blades disposed between an inner-diameter surface and an outer-diameter surface. The turbine blades are of a front or intermediate loaded type near the inner-diameter surface and of a rear loaded type near the outer-diameter surface.

Abstract: A centrifugal or mixed flow type turbomachine, of a vaneless diffuser type can operate stably at low flow rates below the design flow rate, by preventing the initiation of flow instability in the system. The turbomachine comprises two stabilization members disposed in two predetermined locations of the diffuser section which prevents a generation of unstable flow in the diffuser section during a low flow rate operation and reduction of head coefficient in the turbomachine.

Abstract: The present invention provides a centrifugal turbomachinery having a good performance which can effectively reduce the secondary flow in the flow passage of the impeller and minimize the loss caused by the secondary flow without an excessive increase in manufacturing cost. An impeller has a plurality of blades (3) between an inlet (6a) at a central portion and an exit (6b) at a peripheral portion, and a flow passage formed between the blades for delivering fluid from the impeller inlet to the impeller exit by rotation the impeller. The blade (3) is leaned toward a circumferential direction so that the blade at the hub side (2) precedes the blade at the shroud side (4) in a rotational direction of the impeller. A blade lean angle, defined as an angle between the blade and a surface perpendicular to a hub surface as viewed from the direction of the exit, shows a decreasing tendency from the inlet to the exit.

Abstract: A centrifugal or mixed flow type turbomachine, of a diffuser type can operate stably at low flow rates below the design flow rate, by preventing the initiation of flow instability in the system. The turbomachine comprises a stabilization member disposed in a predetermined location of the diffuser section which prevents a generation of unstable flow in the diffuser section during a low flow rate operation.

Abstract: An impeller in a turbomachinery has blades designed such that reduced static pressure difference .DELTA.Cp between the hub and the shroud on the suction surface of the blade shows a remarkably decreasing tendency near the impeller exit as it approaches the impeller exit between the impeller inlet and the impeller exit.

Abstract: Driven turbomachinery for use in centrifugal and mixed flow pump overcomes operational for overcoming difficulties, such as flow separation and generation of surge at low flow rates, often encountered in similar machines of the conventional design. The turbomachinery is provided with variable-angle inlet guide vane and variable-angle diffuser vanes, and the diffuser section is constructed according to a fluid dynamic principle, and the vanes having a wing shape are distributed tangentially so that the diffuser section acts as a centrifugal diffuser. A convenient operational parameter, chosen from such variables as input current to the drive motor, rotational speed or torque of the drive motor, inlet/exit pressures, and fluid velocity, is monitored during the operation by means of sensors strategically attached to parts of the operating system.

Abstract: A turbomachine having variable angle diffuser vanes is demonstrated with the use of a centrifugal pump. The performance of a diffuser is enhanced greatly by the use of adjustable angle diffuser vanes which can be set to a wide range of vane angles to provide a variable size of an opening between adjacent vanes. The demonstrated pumping system has a significantly wider operating range than that in conventional pumping systems over a wide flow rate, and is particularly effective in the low flow range in which known diffuser vane arrangements would lead to surge in the entire system and other serious operational problems. A number of examples and formulae are given to demonstrate the computational methods used to select a vane angle for a given set of operating conditions of the turbomachine.

Abstract: A turbomachine having variable-angle diffuser vanes operates by regulating the angle of the diffuser vanes on the basis of the sensors disposed on the pump body or pipes of a surge detection device. The onset of surge can be forecast by measuring the fluctuations in the operating parameter(s) over a measuring interval of time computed on the basis of the operating characteristics of the impeller of the turbomachine. The onset of surge is prevented by adjusting the angle of the diffuser vanes in accordance with the sampling duration for parameter fluctuations over the measuring interval of time, and by adjusting the diffuser vanes to maintain the operating parameter fluctuations of the fluid machinery below a threshold value of the turbomachine derived from the design flow rate of the turbomachine. Application of the surge detection device in combination with fluid flow guide vanes and blades of the turbomachine enables full utilization of the potential capability of the turbomachine.

Abstract: A turbomachine having variable angle diffuser vanes wed with a centrifugal pump. The performance of a diffuser is greatly enhanced by the use of adjustable angle diffuser vanes which can be set to a wide range of vane angles to provide a variable size of an opening between adjacent vanes. The demonstrated pumping system has a significantly wider operating range than that in conventional pumping systems over a wide flow rate, and is particularly effective in the low flow rate range in which known diffuser vane arrangements would lead to surge in the entire system and other serious operational problems.

Abstract: A turbomachinery is presented to provide stable operation at fluid flow rates much lower than the design flow rate without introducing surge in the device. This is achieved by providing a diffuser with variable angle vanes. The vane angle at low flow rates is adjusted so as to minimize the diffuser loss of the exiting fluid stream from the impeller. Since the flow angle of the exit flow of the impeller is a function only of the non-dimensional flow rates, and does not depend on the flow angle at the inlet the impeller, therefore, the vane angles can be regulated to achieve a stable operation of the impeller without producing surge of the turbomachinery at flow rates lower than the design flow rate. To optimize the performance of the turbomachinery, in addition to the variable angle vanes, an inlet guide vane having variable vane angle is provided so that the turbomachinery can be operated at the required flow rate and head pressure.

Abstract: An impeller in a turbomachine has blades designed such that a reduced static pressure difference .DELTA.Cp between a hub and a shroud on a suction surface of a blade has a tendency to remarkably decrease in the vicinity of an impeller exit as it approaches the impeller exit from an inlet.

Abstract: A turbomachine having variable-angle diffuser vanes operates by regulating the angle of the diffuser vanes on the basis of the sensors disposed on the pump body or pipes of a surge detection device. The onset of surge can be forecast by measuring the fluctuations in the operating parameter(s) over a measuring interval of time computed on the basis of the operating characteristics of the impeller of the turbomachine. The onset of surge is prevented by adjusting the angle of the diffuser vanes in accordance with the sampling duration for parameter fluctuations over the measuring interval of time, and by adjusting the diffuser vanes to maintain the operating parameter fluctuations of the fluid machinery below a threshold value of the turbomachine derived from the design flow rate of the turbomachine. Application of the surge detection device in combination with fluid flow guide vanes and blades of the turbomachine enables full utilization of the potential capability of the turbomachine.

Abstract: A turbomachinery is presented to provide stable operation at fluid flow rates much lower than the design flow rate without introducing surge in the device. This is achieved by providing a diffuser with variable angle vanes. The vane angle at low flow rates is adjusted so as to minimize the diffuser loss of the exiting fluid stream from the impeller. Since the flow angle of the exit flow of the impeller is a function only of the non-dimensional flow rates, and does not depend on the flow angle at the inlet the impeller, therefore, the vane angles can be regulated to achieve a stable operation of the impeller without producing surge of the turbomachinery at flow rates lower than the design flow rate. To optimize the performance of the turbomachinery, in addition to the variable angle vanes, an inlet guide vane having variable vane angle is provided so that the turbomachinery can be operated at the required flow rate and head pressure.

Abstract: A vaned diffuser for centrifugal and mixed flow pumps which has vanes in two rows radially displaced from each other, wherein the vanes are arranged in an optimal positional relationship to each other to improve the diffuser performance with the total pressure loss coefficient and the static pressure recovery coefficient. The vaned diffuser includes vanes arranged in a fluid flow field defined at the outer periphery of an impeller of a centrifugal or mixed flow pump. The vanes are circumferentially arranged in two rows, that is, a first row and a second row, which are equal in number of vanes and radially displaced from each other such that the respective chords of each pair of adjacent vanes in the first and second rows are approximately parallel to each other, and the trailing edges of the vanes in the first row and the leading edges of the vanes in the second row are radially spaced from each other at a distance .DELTA.R=0.05 L to 0.4 L, where L is the chord length of the vanes in the first row.