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

Abstract

The invention discloses a series of three-dimensional flow curved centrifugal impellers for high specific speed and 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 main blade rim curve is 0.59 to 0.77, the ratio of the length of the splitter blade hub curve to the main blade hub curve is 0.63 to 0.83, the main blade wrap angle is 57° to 90°, the inlet installation angle is 25° to 42°, the main blade and the splitter blade outlet installation angle is 25° to 37°, the outlet forward inclination angle is 8° to 40°, the outlet blade width and the maximum outer diameter of the impeller ratio is 0.06 to 0.08, compared with the traditional impeller, the aerodynamic performance of the impeller is greatly improved, the design point adiabatic efficiency can reach 94%, and the high efficiency variable load width, small load fluctuation, the rotor operation is safer and more stable, and the matching problem of large flow and small pressure ratio centrifugal impeller and air bearing when designing is solved.

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 high specific speed and 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] However, the working characteristics of the air bearing require that the working speed of the centrifugal impeller be within the range of 16,000 to 120,000 revolutions per minute. When designing an impeller with large flow and small pressure ratio, the design speed is often lower than the constraint of the minimum speed of the air bearing. Therefore, it is necessary to adopt a solution to increase the specific speed to appropriately increase the working speed of the centrifugal impeller. At the same time, to achieve the same pressure ratio, the high specific speed design can increase the flow capacity of the blades, reduce the wheel size of the centrifugal impeller, make the whole machine structure more compact, improve the economic efficiency of equipment processing, and reduce the space requirements when the equipment is used.

[0004] The existing centrifugal impeller design technology uses a relatively high speed to design centrifugal impellers for large flow and small pressure ratio conditions, which will increase the vortex loss and load fluctuation in the blades, reduce the flow efficiency and rotor stability of the blades, and increase the probability of bearing system damage or machine failure. How to design high-efficiency and high-specific-speed centrifugal impellers for large flow and small pressure ratio conditions so that they can reach the use range of air bearings and meet the requirements of pneumatics, strength and rotor stability has become a problem that air-floating direct-drive blower companies need to solve urgently. Summary of the invention

[0005] The purpose of the present invention is to provide a series of three-dimensional flow curved centrifugal impellers for high specific speed and high efficiency blowers in order to solve the above problems.

[0006] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0007] A series of three-dimensional flow curved centrifugal impellers for high specific speed and high efficiency blowers, wherein the centrifugal impellers in the series of three-dimensional flow curved centrifugal impellers for high 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 0.77 and greater than or equal to 0.59, 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 0.83 and greater than or equal to 0.63.

[0008] 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 0.66 and greater than or equal to 0.42.

[0009] 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 40% to 60%, the minimum area is located at the trailing edge outlet, and the ratio of the minimum flow area to the maximum flow area ranges from 0.61 to 0.86.

[0010] The wrap angle of the main blade 1 is 57° to 90°.

[0011] The inlet installation angle of the main blade 1 is 25° to 42°.

[0012] The outlet installation angles of the main blade 1 and the splitter blade 2 are 25° to 37°.

[0013] The hub curve and the rim curve on the meridian plane of the centrifugal impeller are Bezier curves or beta spline curves.

[0014] The main blades 1 and the splitter blades 2 of the centrifugal impeller have an outlet forward inclination angle of 8° to 40°.

[0015] The ratio of the centrifugal impeller outlet blade width to the impeller maximum outer diameter is 0.06 to 0.08.

[0016] 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 51° to 75°. 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 78° to 100°.

[0017] 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 100% arc length, i.e., the impeller outlet position, and the maximum difference is between 0.002 and 0.022.

[0018] The beneficial effects of the present invention are:

[0019] The present invention proposes a three-dimensional flow curved centrifugal impeller series of high-speed and high-efficiency blowers with low cost and high aerodynamic efficiency. The impeller has the characteristics of being able to operate at a relatively high speed under large flow and small pressure ratio conditions, and can effectively reduce the vortex loss and load fluctuation in the centrifugal impeller blade grid. The insulation efficiency of the impeller design point can reach 94%, and it has a wide range of high-efficiency variable load capacity, and the rotor operation is more stable, avoiding the bearing system damage or the occurrence of the whole machine accident caused by excessive load fluctuation when using the traditional high-speed impeller. The high-efficiency and high-speed centrifugal impeller designed for large flow and small pressure ratio conditions proposed by the present invention has a working speed range that can be well matched with the air-floating bearing, meeting the requirements of aerodynamics, strength and rotor stability, and will provide solid technical support for the air-floating blower with large flow and small pressure ratio conditions to replace the high-energy consumption Roots blower, and make a contribution to the cause of energy conservation and emission reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of a centrifugal impeller of the three-dimensional flow curved surface centrifugal impeller series of the high specific speed and high efficiency blower of the present invention. DETAILED DESCRIPTION

[0021] The present invention will be further described below in conjunction with the accompanying drawings:

[0022] like Figure 1 As shown, the centrifugal impeller of the high specific speed and high efficiency blower three-dimensional flow curved surface centrifugal impeller series 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 0.77 and greater than or equal to 0.59, 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 0.83 and greater than or equal to 0.63.

[0023] 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 the hub curve thereof is less than or equal to 0.66 and greater than or equal to 0.42.

[0024] 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 40% to 60%, the minimum area is located at the trailing edge outlet, and the ratio of the minimum flow area to the maximum flow area ranges from 0.61 to 0.86.

[0025] As a preferred embodiment of the present invention, the wrap angle of the main blade 1 is 57° to 90°.

[0026] As a preferred embodiment of the present invention, the inlet installation angle of the main blade 1 is 25° to 42°.

[0027] As a preferred embodiment of the present invention, the outlet installation angles of the main blades 1 and the splitter blades 2 are 25° to 37°.

[0028] 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.

[0029] 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 8° to 40°.

[0030] As a preferred embodiment of the present invention, the ratio of the centrifugal impeller outlet blade width to the impeller maximum outer diameter is 0.06 to 0.08.

[0031] 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 51° to 75°, 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 78° to 100°.

[0032] 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 100% arc length, i.e., the impeller outlet position, and the maximum difference is between 0.002 and 0.022.

[0033] 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 high specific speed and high efficiency blower, characterized in that: The high 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 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 0.77 and greater than or equal to 0.59, 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 0.83 and greater than or equal to 0.63, the ratio of the rim curve length 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 0.66 and greater than or equal to 0.42, 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 40% to 60%, 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 0.61 to 0.86, the main blade (1) The wrap angle is 57° to 90°, the main blade (1) inlet installation angle is 25° to 42°, the main blade (1) and the splitter blade (2) outlet installation angle is 25° to 37°, the main blade (1) and the splitter blade (2) outlet forward inclination angle of the centrifugal impeller is 8° to 40°, the ratio of the centrifugal impeller outlet blade width to the impeller maximum outer diameter is 0.06 to 0.08, the angle between the rim curve on the meridian plane of the centrifugal impeller and the horizontal axis from the leading edge to the tail is 0.06 to 0.08, and the angle between the rim curve and the horizontal axis on the meridian plane of the centrifugal impeller is 0.06 to 0.

08. The angle at the rim outlet is 51° to 75°, the angle between the hub curve and the horizontal axis on the meridian plane of the centrifugal impeller gradually increases from the leading edge to the trailing edge, and the angle at the hub outlet is 78° to 100°, 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 100% arc length, i.e., the impeller outlet position, and the maximum difference is between 0.002 and 0.

022.

2. The high specific speed and high efficiency blower three-dimensional flow curved surface centrifugal impeller 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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