Medium specific speed high efficiency blower three-dimensional flow curved surface centrifugal impeller series

Abstract

The invention discloses a series of three-dimensional flow curved surface centrifugal impellers for medium specific speed high-efficiency blowers. The centrifugal impellers in the series include 6 to 10 blade groups, the ratio of the length of the splitter blade rim curve to the length of the main blade rim curve is 0.61 to 0.87, the ratio of the length of the splitter blade hub curve to the length of the main blade hub curve is 0.62 to 0.86, the main blade wrap angle is 66° to 100°, the inlet installation angle is 27° to 47°, the main blade and the splitter blade outlet installation angle is 33° to 51°, the outlet forward inclination angle is ‑7° to 27°, the outlet blade width and the maximum outer diameter ratio of the impeller is 0.058 to 0.087, the impeller has high aerodynamic efficiency, low load fluctuation, wide variable load range, the design point adiabatic efficiency can reach 95.3%, the rotor runs safely and stably, and the gas bearing damage or the occurrence of whole machine accidents caused by excessive load fluctuation when the traditional medium specific speed blade type is used is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of gas compression, and in particular to a three-dimensional flow curved surface centrifugal impeller series for a medium specific speed high efficiency blower. Background Art

[0002] The electricity consumption of blowers, compressors, pumps and other equipment accounts for about one-third of the annual power generation. Improving the energy efficiency of the above equipment will directly reduce the electricity expenditure and carbon emission indicators of enterprises. Roots blowers are widely used in the fields of chemical industry, sewage treatment, cement, etc. Due to their low energy efficiency, high noise and oil pollution, they can no longer meet the national energy conservation and emission reduction and user needs. The air-floating direct-drive blower has the advantages of high energy efficiency, near-zero friction, oil-free lubrication and small size. It is considered to be the next generation of high-performance equipment to replace traditional Roots blowers.

[0003] The medium specific speed impeller is the type of impeller that best matches the bearing speed of the air-floating direct-drive blower. However, the adiabatic efficiency of the existing medium specific speed centrifugal impeller is generally between 75% and 82%. This is because the vortices and turbulent boundary layers in the blade grid are prone to interact during the design of the medium specific speed impeller, and the vortex structures of different scales cause load fluctuations in the blade grid, which reduces the flow efficiency and rotor stability of the blade grid and increases the probability of damage to the bearing system or machine accidents. How to design a medium specific speed centrifugal impeller so that it has high efficiency, low load fluctuation, and a wide variable load range within the air-floating bearing speed range, and meets the requirements of aerodynamics, strength, and rotor stability, has become a difficult problem that air-floating direct-drive blower companies need to solve urgently. Summary of the invention

[0004] The purpose of the present invention is to provide a series of three-dimensional flow curved centrifugal impellers for medium specific speed and high efficiency blowers in order to solve the above problems.

[0005] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0006] A series of three-dimensional flow curved centrifugal impellers for medium specific speed and high efficiency blowers, wherein the centrifugal impellers of the series of three-dimensional flow curved centrifugal impellers for medium specific speed and high efficiency blowers include 6 to 10 blade groups, each blade group includes a main blade 1 and a splitter blade 2, the ratio of the rim curve length of the splitter blade 2 to the rim curve length of the main blade 1 is less than or equal to 0.87 and greater than or equal to 0.61, and the ratio of the hub curve length of the splitter blade 2 to the hub curve length of the main blade 1 is less than or equal to 0.86 and greater than or equal to 0.62.

[0007] The ratio of the length of the rim curve of the splitter blade 2 on the meridian plane of the centrifugal impeller to the length of the hub curve thereof is less than or equal to 0.78 and greater than or equal to 0.51.

[0008] The centrifugal impeller has a positive flow area that increases first and then decreases from the leading edge to the trailing edge of the blade, the maximum positive flow area is at a relative position of 21% to 40%, the minimum area is located at the trailing edge outlet, and the ratio of the minimum flow area to the maximum flow area is in the range of 0.65 to 0.92.

[0009] The wrap angle of the main blade 1 is 66° to 100°.

[0010] The inlet installation angle of the main blade 1 is 27° to 47°.

[0011] The outlet installation angles of the main blade 1 and the splitter blade 2 are 33° to 51°.

[0012] The hub curve and the rim curve on the meridian plane of the centrifugal impeller are Bezier curves or beta spline curves.

[0013] The outlet forward inclination angles of the main blades 1 and the splitter blades 2 of the centrifugal impeller are -7° to 27°.

[0014] The ratio of the centrifugal impeller outlet blade width to the impeller maximum outer diameter is 0.058 to 0.087.

[0015] The angle between the rim curve on the meridian plane of the centrifugal impeller and the horizontal axis gradually increases from the leading edge to the trailing edge, and the angle at the rim outlet is 61° to 88°. The angle between the hub curve on the meridian plane of the centrifugal impeller and the horizontal axis gradually increases from the leading edge to the trailing edge, and the angle at the hub outlet is 73° to 100°.

[0016] The maximum difference between the curvature curve of each point on the rim curve of the centrifugal impeller and the curvature curve of each point on the hub curve corresponding to the same arc length percentage is located at 40% to 70% of the arc length and is not greater than 0.022.

[0017] The beneficial effects of the present invention are:

[0018] The present invention proposes a three-dimensional flow curved surface centrifugal impeller series of medium-specific speed high-efficiency blowers with low cost and high insulation efficiency. The blade type adopts a high-precision turbulent boundary layer and vortex system analysis method to identify the vortex system structure and control the flow field, which minimizes the number and influence range of large-scale vortices in the flow field, and has the ability to operate with relatively high insulation efficiency under wide load conditions, effectively reducing the vortex loss and load fluctuation in the centrifugal impeller blade grid. The insulation efficiency of the impeller design point of the three-dimensional flow curved surface centrifugal impeller series of medium-specific speed high-efficiency blowers can reach 95.3%, and there is a wide range of high-efficiency variable load capacity, the rotor operation is more stable, and the bearing system damage or the occurrence of the whole machine accident caused by excessive load fluctuation when using the traditional high-specific speed blade type is avoided. The high-efficiency medium-specific speed centrifugal impeller proposed by the present invention has a working speed range that can be well matched with the air-floating bearing, meets the requirements of aerodynamics, strength and rotor stability, and can provide solid technical support for the air-floating blower to replace the high-energy-consuming Roots blower, and make a contribution to the cause of energy conservation and emission reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of a centrifugal impeller in the three-dimensional flow curved surface centrifugal impeller series of the specific speed high efficiency blower in the present invention. DETAILED DESCRIPTION

[0020] The present invention will be further described below in conjunction with the accompanying drawings:

[0021] like Figure 1 As shown, the centrifugal impeller of the three-dimensional flow curved centrifugal impeller series of the medium specific speed high-efficiency blower includes 6 to 10 blade groups, each blade group includes a main blade 1 and a splitter blade 2, the ratio of the rim curve length of the splitter blade 2 to the rim curve length of the main blade 1 is less than or equal to 0.87 and greater than or equal to 0.61, and the ratio of the hub curve length of the splitter blade 2 to the hub curve length of the main blade 1 is less than or equal to 0.86 and greater than or equal to 0.62.

[0022] As a preferred embodiment of the present invention, the ratio of the length of the rim curve of the splitter blade 2 on the meridian plane of the centrifugal impeller to the length of its hub curve is less than or equal to 0.78 and greater than or equal to 0.51.

[0023] As a preferred embodiment of the present invention, the centrifugal impeller has a positive flow area that first increases and then decreases from the leading edge of the blade to the trailing edge of the blade, the maximum positive flow area is at a relative position of 21% to 40%, the minimum area is located at the trailing edge outlet, and the ratio of the minimum flow area to the maximum flow area is in the range of 0.65 to 0.92.

[0024] As a preferred embodiment of the present invention, the wrap angle of the main blade 1 is 66° to 100°.

[0025] As a preferred embodiment of the present invention, the inlet installation angle of the main blade 1 is 27° to 47°.

[0026] As a preferred embodiment of the present invention, the outlet installation angles of the main blade 1 and the splitter blade 2 are 33° to 51°.

[0027] As a preferred embodiment of the present invention, the hub curve and the rim curve on the meridian plane of the centrifugal impeller are Bezier curves or beta spline curves.

[0028] As a preferred embodiment of the present invention, the outlet forward angles of the main blades 1 and the splitter blades 2 of the centrifugal impeller are -7° to 27°.

[0029] As a preferred embodiment of the present invention, the ratio of the centrifugal impeller outlet blade width to the impeller maximum outer diameter is 0.058 to 0.087.

[0030] As a preferred embodiment of the present invention, the angle formed by the rim curve on the meridian plane of the centrifugal impeller and the horizontal axis gradually increases from the leading edge to the trailing edge, and the angle at the rim outlet is 61° to 88°, and the angle formed by the hub curve on the meridian plane of the centrifugal impeller and the horizontal axis gradually increases from the leading edge to the trailing edge, and the angle at the hub outlet is 73° to 100°.

[0031] As a preferred embodiment of the present invention, the maximum difference between the curvature curve of each point on the rim curve of the centrifugal impeller and the curvature curve of each point on the hub curve corresponding to the same arc length percentage is located at 40% to 70% of the arc length and is not greater than 0.022.

[0032] The technical solution of the present invention is not limited to the above-mentioned specific embodiments. All technical variations made according to the technical solution of the present invention fall within the protection scope of the present invention.

Claims

1. A three-dimensional flow curved surface centrifugal impeller for a medium specific speed high efficiency blower, characterized in that: The medium specific speed high efficiency blower three-dimensional flow curved surface centrifugal impeller comprises 6 to 10 blade groups, each blade group comprises a main blade (1) and a diverter blade (2), the ratio of the rim curve length of the diverter blade (2) to the rim curve length of the main blade (1) is less than or equal to 0.87 and greater than or equal to 0.61, the ratio of the hub curve length of the diverter blade (2) to the hub curve length of the main blade (1) is less than or equal to 0.86 and greater than or equal to 0.62, the ratio of the rim curve length of the diverter blade (2) to the hub curve length on the meridian plane of the centrifugal impeller is less than or equal to 0.78 and greater than or equal to 0.51, the centrifugal impeller has a positive flow area from the leading edge to the trailing edge of the blade that first increases and then decreases, the maximum positive flow area is at a relative position of 21% to 40%, the minimum area is at the trailing edge outlet and the ratio of the minimum flow area to the maximum flow area is in the range of 0.65 to 0.92, the main blade The wrap angle of the centrifugal impeller (1) is 66° to 100°, the inlet installation angle of the main blade (1) is 27° to 47°, the outlet installation angle of the main blade (1) and the splitter blade (2) is 33° to 51°, the outlet forward inclination angle of the main blade (1) and the splitter blade (2) of the centrifugal impeller is -7° to 27°, the ratio of the centrifugal impeller outlet blade width to the impeller maximum outer diameter is 0.058 to 0.087, the rim curve of the centrifugal impeller on the meridian plane is 0.058 to 0.087, and the centrifugal impeller is 0.058 to 0.

087. The angle between the axis and the wheel hub curve on the meridian plane of the centrifugal impeller and the horizontal axis gradually increases from the leading edge to the trailing edge, and the angle at the wheel hub outlet is 61° to 88°. The angle between the axis and the wheel hub curve on the meridian plane of the centrifugal impeller and the horizontal axis gradually increases from the leading edge to the trailing edge, and the angle at the wheel hub outlet is 73° to 100°. The maximum difference between the curvature curve of each point on the wheel hub curve of the centrifugal impeller and the curvature curve of each point on the wheel hub curve corresponding to the same arc length percentage is located at the position of 40% to 70% arc length, and is not greater than 0.

022.

2. The three-dimensional flow curved surface centrifugal impeller for a medium specific speed high efficiency blower according to claim 1, characterized in that: The hub curve and the rim curve on the meridian plane of the centrifugal impeller are Bezier curves or beta spline curves.

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