Influence of Freely Rotating Inlet Guide Vanes on the Return Flows and Stable Operating Range of an Axial Flow Fan
01 Jan 1980-Journal of Engineering for Power (American Society of Mechanical Engineers)-Vol. 102, Iss: 1, pp 75-80
TL;DR: In this paper, the results of experimental investigations on the three-dimensional flow and performance characteristics of a free vortex axial flow fan rotor with a freely rotating and braked inlet guide vane row were presented.
Abstract: This paper presents the results of experimental investigations on the three-dimensional flow and performance characteristics of a free vortex axial flow fan rotor, with a freely rotating and braked inlet guide vane row. The influences of axial distance between the inlet guide vane row and the rotor inlet, inlet guide vane setting angle and shape, partial omission of guide vanes at the hub and tip regions on the return flows have been studied and optimum axial distance and setting angle that will improve the useful operating range of the fan were determined. Use of freely rotating inlet guide vanes at high flow volumes and braked inlet guide vanes at low flow coefficients resulted in a reduction of return flows and an increase of the stable operating range of the axial fan rotor by more than 35 percent and this combination has yielded higher efficiencies as well in the extended region of stable operation.
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Patent•
03 Jun 1994
TL;DR: In this article, a regenerative or toric pump adds energy to a fluid using an impeller having an axis of rotation and axially spaced, radially extending first and second surfaces.
Abstract: A regenerative or toric pump adds energy to a fluid using an impeller having an axis of rotation and axially spaced, radially extending first and second surfaces. A casing encloses the impeller and has a fluid inlet and a fluid outlet separated by a stripper. The casing has axially spaced, radially extending first and second sidewalls facing the first and second surfaces of the impeller respectively. Axially and radially extending blades or vanes are formed on an outer radial periphery of the impeller for driving fluid from the inlet toward the outlet as the impeller rotates about the axis of rotation. A fixed surface is formed in at least one sidewall of the casing for directing fluid back toward the impeller. Improved operating characteristics and extended range are accomplished through modification to the vane configuration of the impeller and/or by modification of the side channel configuration of the pump chamber in an asymmetrical fashion. The vanes can be modified to include a radially inward base portion extending in a generally trailing direction with respect to rotation of the impeller and a radially outward tip portion extending in a generally leading direction. The blades may also include a chamfered surface on the trailing edge of the base portion. The impeller chamber can be modified separately by expanding a side channel in the casing, or by insertion of a spacer between the side channel and the remaining portion of the casing defining the impeller chamber.
29 citations
Patent•
12 Nov 1999TL;DR: In this paper, a regenerative or toric pump adds energy to a fluid using an impeller having an axis of rotation and axially spaced, radially extending first and second surfaces.
Abstract: A regenerative or toric pump adds energy to a fluid using an impeller having an axis of rotation and axially spaced, radially extending first and second surfaces. A casing encloses the impeller and has a fluid inlet and a fluid outlet separated by a stripper. The casing has axially spaced, radially extending first and second sidewalls facing the first and second surfaces of the impeller respectively. Axially and radially extending blades or vanes are formed on an outer radial periphery of the impeller for driving fluid from the inlet toward the outlet as the impeller rotates about the axis of rotation. A fixed surface is formed in at least one sidewall of the casing for directing fluid back toward the impeller. Improved operating characteristics and extended range are accomplished through modification to the vane configuration of the impeller and/or by modification of the side channel configuration of the pump chamber in an asymmetrical fashion. The vanes can be modified to include a radially inward based portion extending in a generally trailing direction with respect to rotation of the impeller and a radially outward tip portion extending in a generally leading direction. The blades may also include a chamfered surface on the trailing edge of the base portion. The impeller chamber can be modified separately by expanding a side channel in the casing, or by insertion of a spacer between the side channel and the remaining portion of the casing defining the impeller chamber.
20 citations
Patent•
17 Feb 1994TL;DR: In this paper, a turbo machine comprising a rotatably mounted blade row, such as a compressing or pumping rotor and apparatus for providing aerodynamic feedback to the blade row which feedback apparatus has substantially zero pressure difference across it.
Abstract: The invention is a turbo machine comprising a rotatably mounted blade row, such as a compressing or pumping rotor and apparatus for providing aerodynamic feedback to the blade row which feedback apparatus has substantially zero pressure difference across it. The feedback may be provided by various apparatus, including at least one free-rotor that is mounted in aerodynamic feedback with the blade row, for instance coaxially with respect to the axis of rotation of the blade row and freely rotatably with respect to the blade row. The free-rotor may also be located in ductwork in communication with the blade row. The feedback may also be provided by a blade row having a variable stagger angle and apparatus to adjust the stagger angle so that the mean pressure rise across the variable stagger angle blade row is zero. The invention also includes a method for controlling operating anomalies such as rotating stall and surge of a turbo machine such as a compressor using the above described apparatus.
15 citations
Dissertation•
01 Jan 1999
TL;DR: In this paper, the performance characteristics of an existing variable inlet guide vanes (VIGV's) were determined using both an experimental test facility and state-of-the-art numerical techniques.
Abstract: Industrial centrifugal air compressors can require a combination of a large range of
mass flow, high efficiency, constant pressure ratio, and constant rotational speed,
specifically when used for sewage effluent aeration treatment. In order to achieve this
performance it is common to use variable inlet guide vanes (VIGV's).
The performance characteristics of an existing VIGV design have been determined
using both an experimental test facility and state of art numerical techniques. The
results obtained from these techniques are far more comprehensive than earlier fullscale
performance testing. Validation of the performance of the existing design using
these techniques has led to the development of a new vane design and potential
improvements to the inlet ducting geometry.
The aerodynamic interaction between the VIGV system and the centrifugal
compressor impeller has also been investigated using a 3-D computational model of
the complete variable geometry compressor stage. The results of these investigations
have been validated by data available from full scale experimental testing. Strong
correlation was obtained between numerical and experimental techniques, and a
predicted improvement in polytropic efficiency up to 3% at low flow rates using the
re-designed variable inlet guide vanes has been achieved.
The overall outcome of this research is a usable VIGV design technique for real
industrial compressor environments, and confirmation that an acceptable design can
be achieved that represents a rewarding improvement in performance.
5 citations
01 Jun 2019
TL;DR: In this paper, the effect of the inlet guide vanes on cavitation performance of an axial pump was investigated to assess the mechanism for cavitation in pumps and to improve their performance.
Abstract: The effect of the inlet guide vanes on cavitation performance of an axial pump is investigated to assess the mechanism for cavitation in pumps and improve their cavitation performance. The effect o...
4 citations