Low specific speed 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 low 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 0.57 to 0.81, the ratio of the length of the splitter blade hub curve to the main blade hub curve is 0.61 to 0.86, the main blade wrap angle is 46° to 85°, the inlet installation angle is 30° to 45°, the main blade and the splitter blade outlet installation angle is 39° to 55°, the outlet forward inclination angle is ‑12° to 31°, the ratio of the outlet blade width to the maximum outer diameter of the impeller is 0.033 to 0.057, and compared with traditional impellers, the aerodynamic performance of the impeller is greatly improved, the design point adiabatic efficiency can reach 93%, the variable load range is wide, the load fluctuation is small, the rotor runs more safely and stably, and the matching problem of the small flow and large pressure ratio centrifugal impeller and the 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 of a low 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 rpm. Therefore, for small flow and large pressure ratio impellers, the speed is often higher than the maximum speed constraint of the air bearing. It is necessary to adopt a low specific speed design scheme to further reduce the speed of the centrifugal impeller, increase the volume of the centrifugal impeller, and reduce the flow capacity of the blade grid, so that the impeller strength and processing technology are more in line with the blower working requirements.

[0004] The existing centrifugal impeller design technology, designed for low specific speed centrifugal impellers for small flow and large pressure ratio conditions, will increase the friction 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, low specific speed centrifugal impellers for small flow and large 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 low 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 low specific speed and high efficiency blowers, wherein the centrifugal impellers of the series of three-dimensional flow curved centrifugal impellers for low 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 0.81 and greater than or equal to 0.57, 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 0.61.

[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 0.85 and greater than or equal to 0.6.

[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 66%, 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 0.63 to 0.87.

[0010] The wrap angle of the main blade 1 is 46° to 85°.

[0011] The inlet installation angle of the main blade 1 is 30° to 45°.

[0012] The outlet installation angles of the main blade 1 and the splitter blade 2 are 39° to 55°.

[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 outlet forward inclination angles of the main blades 1 and the splitter blades 2 of the centrifugal impeller are -12° to 31°.

[0015] The ratio of the centrifugal impeller outlet blade width to the impeller maximum outer diameter is 0.033 to 0.057.

[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 75° to 92°. 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 75° 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 0.022 and 0.062.

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

[0019] The present invention proposes a low-cost, high-insulation efficiency, low-specific-speed high-efficiency blower three-dimensional flow curved centrifugal impeller series blade type, which can still run at a relatively high speed under small flow and large 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 93%, 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 the traditional low-specific-speed blade type is used is avoided. The high-efficiency, low-specific-speed centrifugal impeller designed for small flow and large 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 small flow and large pressure ratio conditions to replace the high-energy consumption Roots blower, and make a contribution to 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 low 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 three-dimensional flow curved centrifugal impeller series of low specific speed high-efficiency blowers 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 0.81 and greater than or equal to 0.57, 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 0.61.

[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 its hub curve is less than or equal to 0.85 and greater than or equal to 0.6.

[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 66%, 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 0.63 to 0.87.

[0025] As a preferred embodiment of the present invention, the wrap angle of the main blade 1 is 46° to 85°.

[0026] As a preferred embodiment of the present invention, the inlet installation angle of the main blade 1 is 30° to 45°.

[0027] As a preferred embodiment of the present invention, the outlet installation angles of the main blade 1 and the splitter blade 2 are 39° to 55°.

[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 -12° to 31°.

[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 0.033 to 0.057.

[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 75° to 92°, 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 75° 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 0.022 and 0.062.

[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 low specific speed and high efficiency blower, characterized in that: The three-dimensional curved surface centrifugal impeller of the low specific speed high-efficiency blower 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 0.81 and greater than or equal to 0.57, 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 0.61, the ratio of the rim curve length of the splitter blade (2) to the hub curve length on the meridian plane of the centrifugal impeller is less than or equal to 0.85 and greater than or equal to 0.6, the positive flow area of ​​the centrifugal impeller from the leading edge to the trailing edge of the blade increases first and then decreases, the maximum positive flow area is at a relative position of 40% to 66%, 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 0.63 to 0.87, the wrap angle of the main blade (1) is The main blade (1) has an inlet installation angle of 30° to 45°, the main blade (1) and the splitter blade (2) have an outlet installation angle of 39° to 55°, the main blade (1) and the splitter blade (2) of the centrifugal impeller have an outlet forward inclination angle of -12° to 31°, the ratio of the centrifugal impeller outlet blade width to the maximum outer diameter of the impeller is 0.033 to 0.057, and the angle between the rim curve on the meridian plane of the centrifugal impeller and the horizontal axis is from the leading edge to the trailing edge. The angle at the rim outlet is 75° to 92°, 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 75° 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 0.022 and 0.

062.

2. The three-dimensional flow curved surface centrifugal impeller for a low specific speed and 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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