CN114526249A

CN114526249A - Two-stage centrifugal impeller fan for air pressurization system of breathing machine

Info

Publication number: CN114526249A
Application number: CN202111552049.4A
Authority: CN
Inventors: 李勇; 左云鹏; 杨涛
Original assignee: Kefu Medical Technology Co ltd
Current assignee: Kefu Medical Technology Co ltd
Priority date: 2021-12-17
Filing date: 2021-12-17
Publication date: 2022-05-24

Abstract

The invention relates to a two-stage centrifugal impeller fan for a respirator air pressurization system, which comprises: the device comprises a primary air inlet channel, an outer cover, a primary centrifugal impeller, a motor cover, an interstage air guide impeller, a secondary air inlet channel, a secondary centrifugal impeller, an outlet air guide impeller and a tail cover; an inner rotor brushless motor of the integrated double rotor drives two centrifugal impellers, the rotating speed ranges from 0rpm to 36000rpm, inlet air is accelerated to pass through a first-stage air inlet channel through the first-stage centrifugal impeller, the centrifugal impeller sucks the air and applies work to the air, so that the dynamic pressure of the air is increased, the dynamic pressure of the air is reduced in an air storage channel after the air is expanded, the static pressure is increased, the air flows through an air channel and enters an interstage air guide impeller, and the air flows in the axial direction from radial flow; after entering the secondary air inlet channel, the air is sucked by the secondary centrifugal impeller and does work again to increase the dynamic pressure of the air again, and the air is output after being decelerated and pressurized by the outlet air guide impeller.

Description

Two-stage centrifugal impeller fan for air pressurization system of breathing machine

Technical Field

The invention relates to the technical field of respirators, in particular to a two-stage centrifugal impeller fan for a respirator air supercharging system, which is an axial flow double-rotor centrifugal impeller fan generating strong axial positive pressure difference.

Background

Modern ventilators were first shown in Mol-gaard and Lund in copenhagen 1915, and Giertz, a surgeon in Stockholm 1916, and their achievements were silent and only reported in scientific communications. In 1934 Frenkner developed a first pneumatic pressure limiting ventilator, named "Spiropulsator", whose air source came from a steel cylinder and when inhaling, the air passed through two pressure reducing valves to generate a pressure of 50cm of water. In 1940, Frenkner and craft collaborated, and improved on the basis of "Spiropulsator" so that it can be used simultaneously with cyclopropane, the first anesthetic respirator was made. In 1942, the american engineer Bennett invented an oxygen supply apparatus using on-demand valves for use in high-altitude flights. After the development of the intermittent positive pressure ventilator TV-2P in 1948, it was used to treat acute and chronic respiratory failure. The breathing machine brands Jefferson, Morch, Stephenson, Bennett and bird brands were the most widely used breathing machines in the US market in 1955. In the 60 s, with the rapid development of electronic products, ventilators also entered the electronic era. The application of the breathing machine is wider, and the control of the breathing machine is more accurate. The postoperative respirator of Emerson in 1964 is an electric control respirator, the breathing time can be adjusted at will, and a compressed air pump is equipped, and various functions can be adjusted electronically, so that the era that the traditional respirator belongs to simple mechanical motion is fundamentally changed, and the precise electronic era is spanned. Until 1970, pneumatic ventilators controlled by the jet principle were developed, which are ventilators controlled by a gas flow, sensors, logic elements, amplifiers and regulation functions, etc., all using the jet principle without any moving parts, but with the same effect as the circuit. In the 70 s of the 20 th century, due to the development of scientific technology, many sophisticated technologies, especially electronic technologies, were introduced into the design of ventilators, and a large group of new ventilators were made available. New ventilation concepts and technologies are developed and applied, positive end expiratory pressure, continuous positive airway pressure, intermittent mandatory ventilation and T-tube technology are applied. With the rapid development of computer technology since the 80 s, a new generation of multifunctional computer type breathing machine has functions such as monitoring, alarming, recording and the like which cannot be realized in the past. In the 90 s, the breathing machine is continuously developing towards intellectualization, the application of computer technology enables the function of the breathing machine to be more perfect, and the performance is greatly improved.

The air pressurization system provides a positive pressure air source for the respirator, and is an important key technology for designing the respirator. Breathing machine manufacturers at home and abroad invest a great deal of manpower and material resources in an air pressurization system for research and development, and try to master key technologies of the breathing machine manufacturers. A typical booster system fan includes two main parts: a rotating part, namely a motor for stirring air and lifting air pressure and a rotating fan blade; the fixing part stores a shell and a flow guide fan blade which limit the direction of fluid. The fan structure is mostly that the motor drives a fan blade wrapped in the wind cabin to rotate at a high speed to do work, and the purpose of increasing the gas pressure and the flow speed is achieved by the gap difference between the fan blade and the shell.

The total pressure ratio of the existing air pressurization system is usually 1.025 times, and the isentropic efficiency index is 50%. Most noninvasive ventilators all use the single-impeller air-blower of terminal surface air inlet, side air-out, and the wind that the terminal surface came in is through the high-speed pressurization of impeller circulation strike the blast hood until export through the air outlet, and it is higher to require the motor rotational speed when this in-process total pressure ratio exceeds 1.025 times, and the circulation strikes the blast hood and leads to diversified noise stack. The main technical difficulty of designing the air pressurization system is to enable the shaft power of the air pressurization system and the brushless motor to be matched through the optimization design of parameters such as the geometric shape, the number of blades, the diameter and the rotating speed of the fan blades of the air pressurization system, so as to obtain higher pressure ratio and higher efficiency. Therefore, the optimal design of the pneumatic appearance of the air system of the breathing machine must rely on a large computational fluid dynamics numerical simulation software platform and a high-performance computer to carry out numerical calculation, and the air pressurization system of the breathing machine with excellent performance is obtained by combining the computational fluid dynamics technology, the ground test testing technology, the material technology, the manufacturing technology and the like.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the performance of the air pressurization system of the existing respirator is overcome, and the air pressurization system suitable for low rotating speed, high pressure rise and large flow is provided.

In order to achieve the above object, the present invention provides a two-stage centrifugal impeller fan for a ventilator air booster system, comprising two opposite centrifugal impellers (3, 9).

Further, the device comprises a primary air inlet channel (1), an outer cover (2), a primary centrifugal impeller (3), a motor A (4), an integrated supporting end cover (5), a motor B (6), an interstage air guide impeller (7), a secondary air inlet channel (8), a secondary centrifugal impeller (9), an outlet air guide impeller (10) and a tail cover (11); the tail part of the primary air inlet channel (1) is arranged on the outer cover (2), the primary centrifugal impeller (3) is arranged on a front end shaft of the motor A (4), the integral supporting end cover (5) is arranged on the outer cover (2), and the motor A (4) and the motor B (6) are respectively arranged at two ends of the integral supporting end cover (5) and used for driving the impeller to rotate; the interstage guide air wheel (7) is installed on the motor B (6), the secondary air inlet channel (8) is installed on the interstage guide air wheel (7), the secondary centrifugal impeller (9) is installed on a tail section shaft of the motor B (6), the outlet guide air impeller (10) is installed on the tail cover (11), and the tail cover (11) is connected with the outer cover (2) and sealed. The device mainly comprises a primary air inlet channel (1), an outer cover (2), a primary centrifugal impeller (3), a motor A (4), an integrated supporting end cover (5), a motor B (6), an interstage air guide impeller (7), a secondary air inlet channel (8), a secondary centrifugal impeller (9), an outlet air guide impeller (10) and a tail cover (11).

The invention abandons the traditional motor structure, adopts a unique integrated supporting end cover structure, the integrated supporting end cover is a supporting system of the whole fan, the integrated supporting end cover is used as a central support, an outer cover is supported, a motor A (4) and a motor B (6) are supported, and bearing positions of motor shells at two ends and bearing positions of the integrated supporting end cover are respectively coaxially aligned; the two rotors are fixed at the inner ends of the stator coils through the bearing inner rings; motor A and motor B and integrative support end cover surround rotor and bearing inside the motor, such design safety, the reliability is high, can guarantee that rotor concentricity and bearing grease are difficult to air-dry.

The invention adopts an integral double-rotor inner rotor brushless motor, the double rotors and the coils can be electrified and work simultaneously or independently, (a common blower only has a single motor), once one group of coils or one group of rotors has a fault, the power supply at the fault end can be cut off rapidly, the other group of motors can still rotate limitedly to provide air pressure (emergency action), and the setting can play a role in saving under special occasions.

The double rotors are also inner rotors, the centrifugal impeller can be conveniently placed in the structural form of the inner rotors, and the centrifugal impeller is fixed at the extending end of the rotor shaft, so that the installation is convenient. The two rotors are respectively matched with a centrifugal impeller, the two inner rotors work through the operation of a magnetic field generated by the two groups of coils, the rotating speed of the motor of the inner rotors is high, and the centrifugal impeller can obtain stable high rotating speed as far as possible due to the advantage of small rotating inertia, and meanwhile, the centrifugal impeller has better effects on the aspects of motor vibration and noise.

The brushless motor drives the centrifugal impeller to rotate, the rotating speed range is 0-36000 rpm (Revolutions Per Minute), air is accelerated to reach the inlet speed of the first-stage centrifugal impeller through the first-stage air inlet channel, the centrifugal impeller sucks the air and applies work to the air, so that the dynamic pressure of the air is increased, the air is expanded, the dynamic pressure is reduced, the static pressure is increased, the air flows through an air channel between the outer side of the motor cover and the inner side of the outer cover to enter the interstage air guide impeller, and the air flows in the radial direction and then flows in the axial direction; after the air enters the secondary air inlet channel, the secondary centrifugal impeller sucks the air and applies work to the air again, so that the dynamic pressure of the air is increased again, and the air is output after being accelerated by the outlet air guide impeller.

The first-stage air inlet channel is mainly used for air inlet and rectification, guiding airflow to accelerate, inhibiting separation and reducing flow loss. The airflow reaches a certain speed after passing through the first-stage air inlet channel and is matched with the rotating speed of the first-stage centrifugal impeller, so that the stalling phenomenon of the centrifugal impeller at the inlet is avoided.

Furthermore, the ratio of the throat area to the inlet area of the V-shaped first-stage air inlet channel is 1: 1.1-1: 1.4, the half cone angle of the air inlet channel is 5-15 degrees, and the length of the air inlet channel is 5-10 mm. The first-stage air inlet channel is directly fixed at the front end of the outer cover.

Furthermore, the first-stage centrifugal impeller and the second-stage centrifugal impeller both adopt centrifugal supercharging impellers, the centrifugal impellers are in twisted sweepback pneumatic shapes, and blade installation angles and chord lengths of the centrifugal impellers are gradually reduced along the axial direction of the centrifugal impellers. The distance between the first-stage centrifugal impeller and the front section of the outer cover is 0.1-1 mm.

Furthermore, the number of blades of the first-stage centrifugal impeller is 8-14, the diameter of the impeller is 38-50 mm, the inlet height is 5-10 mm, and the outlet height is 2-4 mm; the method adopts the NACA series airfoil profile developed by the American national aviation council, and the thickness is 10 to 30 percent; the radius of the front edge and the rear edge of the blade is 0.25 mm-1 mm. The helix angle of the blade root is 0-50 degrees along the chord length (0-1), the preferred value of the airflow angle of the leading edge of the blade root is 10-20 degrees, and the airflow angle of the trailing edge of the blade root is 0-15 degrees; the helix angle of the blade tip is 10-50 degrees along the chord length (0-1), the airflow angle of the leading edge of the blade tip is 30-50 degrees, and the airflow angle of the trailing edge of the blade tip is 5-20 degrees.

Furthermore, the interstage air guide impeller is designed in a 90-degree spiral petal type mode, and the number of blades is 4-10; the air guide impeller is a swirler, and changes radial airflow into axial airflow. The area of the interstage air guide impeller channel is in a gradually increasing rule and is designed to be a speed reduction channel, and airflow enters the air guide wheel and then enters the secondary air inlet channel after being subjected to speed reduction and pressure expansion, so that pressure loss caused by flow reversing is reduced. The height of the interstage air guide impeller is 6 mm-16 mm. In order to reduce the airflow separation at the inlet of the air guide impeller, the radiuses of the front edge and the rear edge of the air guide impeller blade are 0.25 mm-0.5 mm, the spiral angles of the blade tip and the blade root are kept consistent with the airflow angle, and the spiral angles are 0. The method adopts NACA series airfoil profile with the thickness of 5-15 percent.

Further, the second-stage centrifugal impeller and the first-stage centrifugal impeller are identical in configuration.

Furthermore, the outlet air guide impeller is designed in a 125-degree spiral petal type mode, and the number of blades is 4-8; the outlet air guide impeller is a swirler, and changes radial airflow into axial airflow. The area of the outlet air guide wheel channel is in a gradually decreasing rule and is designed to be an accelerating channel, and air flow enters the air guide wheel and then is exhausted in an accelerating mode. The height of the outlet air guide impeller is 3 mm-8 mm. In order to reduce the airflow separation at the inlet of the air guide impeller, the radius of the front edge and the rear edge of the air guide impeller blade is 0.1 mm-0.5 mm. The helix angle of the root part of the blade of the air guide impeller is 0-150 degrees along the chord length (0-1), the airflow angle of the leading edge of the blade root is 40-75 degrees, and the airflow angle of the trailing edge of the blade root is 10-30 degrees. The helix angle and the air flow angle of the blade tip and the blade root are kept consistent. The method adopts NACA series airfoil profile with the thickness of 5-15 percent.

Further, the helix angle and the air flow angle of the radial section position of the centrifugal impeller are specifically as follows:

when the distance between the radial section of the centrifugal impeller and the hub is 0, the leading edge helix angle and the airflow angle of the radial section are respectively 0 degree and 20 degrees, the trailing edge helix angle and the airflow angle are respectively 30 degrees and 10 degrees, wherein B is the span length of the centrifugal impeller blade;

when the distance between the radial section of the centrifugal impeller and the hub is 0.5B, the leading edge helix angle and the airflow angle of the radial section are respectively 6 degrees and 24 degrees, the trailing edge helix angle and the airflow angle are respectively 30 degrees and 11 degrees, wherein B is the span length of the centrifugal impeller blade;

when the distance between the radial section of the centrifugal impeller and the hub is 0.75B, the leading edge helix angle and the airflow angle of the radial section are respectively 10 degrees and 29 degrees, the trailing edge helix angle and the airflow angle are respectively 32 degrees and 12 degrees, wherein B is the span length of the centrifugal impeller blade;

when the distance between the radial section of the centrifugal impeller and the hub is 1B, the leading edge helix angle and the airflow angle of the radial section are 14 degrees and 40 degrees respectively, the trailing edge helix angle and the airflow angle are 33 degrees and 14 degrees respectively, and B is the span length of the centrifugal impeller blade.

Aiming at the working conditions of the air pressurization system of the respirator, the invention utilizes CFD to carry out numerical simulation and geometric parameter optimization design to obtain the pneumatic shapes of a centrifugal impeller, an interstage guide gas wheel and an outlet guide gas wheel with high pressure ratio and high isentropic efficiency. Adopt unique integrative bearing structure to integrative supporting end cover is the center support, is equipped with 2 bearing positions respectively, is equipped with two sets of rotors, and a centrifugal impeller is respectively matchd to the birotor. The two groups of rotors and the two groups of coils can be electrified and work independently at the same time. The inner rotor has compact structure, better overall layout of the motor, integration of the rotor and the centrifugal impeller and more contribution to air duct design, and the double-rotor structure ensures that the motor has high rotating speed and small rotational inertia, so that a fan with higher air pressure and larger flow can be designed, and the design problem of an air flowing air cavity is better solved.

Drawings

FIG. 1 is a schematic size view of an air booster fan according to the present invention;

FIG. 2 is a schematic view of an air booster fan assembly according to the present invention;

FIG. 3 is a schematic view of structural components of a booster fan according to the present invention;

FIG. 4 is a schematic size diagram of a centrifugal impeller according to an embodiment of the present invention;

FIG. 5 is a schematic size view of an interstage gas guide impeller in an embodiment of the invention;

FIG. 6 is a schematic size view of an outlet gas directing impeller according to an embodiment of the present invention;

FIG. 7 is a schematic diagram of an integrated dual rotor brushless motor assembly according to the present invention;

FIG. 8 is a schematic view of the leading edge and trailing edge of a blade according to the present invention;

the device comprises a primary air inlet channel (1), an outer cover (2), a primary centrifugal impeller (3), a motor A (4), an integrated supporting end cover (5), a motor B (6), an interstage air guide impeller (7), a secondary air inlet channel (8), a secondary centrifugal impeller (9), an outlet air guide impeller (10) and a tail cover (11);

12-a gas flow path;

511-motor front end shaft, 512-motor A front end bearing, 513 primary winding-, 514-motor A rotor magnetic steel, 515-motor A stator silicon steel sheet, 516-motor A casing, 517-motor A rear end bearing;

521-secondary winding, 522-motor B rear end bearing, 523-motor B magnetic steel, 524-motor B stator silicon steel sheet, 525-motor B front end bearing, 526-motor B casing, 527-motor rear end shaft

531-integrally supporting the end cap,

Detailed Description

It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Referring to fig. 1 and 2, the invention provides a two-stage centrifugal impeller fan for a respirator air supercharging system, which mainly comprises a first-stage air inlet channel (1), an outer cover (2), a first-stage centrifugal impeller (3), a motor A (4), an integrated supporting end cover (5), a motor B (6), an interstage air guide impeller (7), a second-stage air inlet channel (8), a second-stage centrifugal impeller (9), an outlet air guide impeller (10) and a tail cover (11).

The tail of one-level intake duct (1) is installed on outer cover (2), and one-level centrifugal impeller (3) are installed on the front end of motor A (4) is epaxial, and integrative support end cover (5) are installed on outer cover (2), and motor A (4) and motor B (6) are installed respectively at integrative support end cover both ends for the drive impeller rotates.

The interstage air guide wheel 7 is arranged on the motor cover 6, the secondary air inlet channel 8 is arranged on the interstage air guide wheel 7, the secondary centrifugal impeller 9 is arranged on a tail section shaft of the motor 5, the outlet air guide impeller 10 is arranged on a tail cover 11, and the tail cover 11 is connected with the outer cover 2 and is sealed.

The invention abandons the traditional motor structure, adopts a unique integrated supporting end cover structure, the integrated supporting end cover is a supporting system of the whole fan, the integrated supporting end cover is used as a central support, an outer cover is supported, a motor A (4) and a motor B (6) are supported, and bearing positions of motor shells at two ends and bearing positions of the integrated supporting end cover are respectively coaxially aligned; the two rotors are fixed at the inner ends of the stator coils through the inner rings of the bearings; motor A and motor B and integrative support end cover surround rotor and bearing inside the motor, such design safety, the reliability is high, can guarantee that rotor concentricity and bearing grease are difficult to air-dry.

The invention adopts an integral double-rotor inner rotor brushless motor, the double rotors and the coils can be electrified and work simultaneously or independently, (a common blower only has a single motor), once one group of coils or one group of rotors have faults, the power supply of the fault end can be cut off rapidly, the other group of motors can still rotate in a limited way to provide air pressure (emergency action), and the setting can play a role in saving under special occasions.

The double rotors are also inner rotors, the centrifugal impeller can be conveniently placed in the structural form of the inner rotors, and the centrifugal impeller is fixed at the extending end of the rotor shaft, so that the installation is convenient. The double rotors are respectively matched with a centrifugal impeller, the two inner rotors work through the operation of magnetic fields generated by the two groups of coils, the rotating speed of the motor of the inner rotors is high, and the centrifugal impeller can obtain stable high rotating speed as far as possible due to the advantage of small rotating inertia, and meanwhile, the double rotors have better effects on the aspects of motor vibration and noise.

The gas flow path of the ventilator air plenum system is shown in fig. 3. The brushless motor drives the centrifugal impeller to rotate, the rotating speed range is 0-36000 rpm (Revolutions Per Minute), air is accelerated to reach the inlet speed of the first-stage centrifugal impeller through the first-stage air inlet channel, the centrifugal impeller sucks the air and applies work to the air, so that the dynamic pressure of the air is increased, the air is expanded, the dynamic pressure is reduced, the static pressure is increased, the air flows through an air channel between the outer side of the shell and the inner side of the outer cover to enter the interstage air guide impeller, and the air flows in the radial direction and then flows in the axial direction; after the air enters the secondary air inlet channel, the secondary centrifugal impeller sucks the air and applies work to the air again to increase the dynamic pressure of the air again; after the air enters the outlet air guide impeller, the dynamic pressure is reduced, the static pressure is increased, the airflow changes from radial to axial flow again, and finally the airflow is ejected through the air outlet of the tail cover.

Furthermore, the ratio of the throat area to the inlet area of the V-shaped first-stage air inlet channel is 1: 1.1-1: 1.4, the half cone angle of the air inlet channel is 5-15 degrees, and the length of the air inlet channel is 5-10 mm.

Further, as shown in fig. 4, the number of blades of the first-stage centrifugal impeller is 8-14, the diameter of the impeller is 38-50 mm, the inlet height is 5-10 mm, and the outlet height is 2-4 mm; the method adopts the NACA series airfoil profile developed by the American national aviation council, and the thickness is 10 to 30 percent; the radius of the front edge and the rear edge of the blade is 0.25 mm-1 mm. The helix angle of the blade root is 0-50 degrees along the chord length (0-1), the preferred value of the airflow angle of the leading edge of the blade root is 10-20 degrees, and the airflow angle of the trailing edge of the blade root is 0-15 degrees; the helix angle of the blade tip is 10-50 degrees along the chord length (0-1), the airflow angle of the leading edge of the blade tip is 30-50 degrees, and the airflow angle of the trailing edge of the blade tip is 5-20 degrees.

Furthermore, the interstage air guide impeller adopts a 90-degree spiral petal type design, and the number of blades is 4-10, as shown in FIG. 5; the interstage air guide impeller is a swirler, and changes radial airflow into axial airflow. The area of the interstage air guide impeller channel is in a gradually increasing rule and is designed to be a speed reduction channel, and airflow enters the air guide wheel and then enters the secondary air inlet channel after being subjected to speed reduction and pressure expansion, so that pressure loss caused by flow reversing is reduced. The height of the interstage air guide impeller is 6 mm-16 mm. In order to reduce airflow separation at the inlet of the air guide impeller, the radius of the front edge and the rear edge of each air guide impeller blade is 0.25-0.5 mm, the optimal value of the helix angle of the root part of each interstage air guide impeller blade along the chord length (0-1) is 0-90 degrees, the helix angle of the blade tip and the blade root is consistent with the airflow angle, and the helix angles are 0. The method adopts NACA series airfoil profile with the thickness of 5-15 percent.

Furthermore, the geometric configuration of the second-stage centrifugal impeller is the same as that of the first-stage centrifugal impeller.

Further, the outlet air guide impeller adopts a 125-degree spiral petal type design, as shown in fig. 6, the number of blades is 4-8; the outlet air guide impeller is a swirler, and changes radial airflow into axial airflow. The area of the outlet air guide wheel channel is in a gradually decreasing rule and is designed to be an accelerating channel, and air flow enters the air guide wheel and then is exhausted in an accelerating mode. The height of the outlet air guide impeller is 3 mm-8 mm. In order to reduce the airflow separation at the inlet of the air guide impeller, the radius of the front edge and the rear edge of the air guide impeller blade is 0.1 mm-0.5 mm. The helix angle of the root part of the blade of the air guide impeller is 0-150 degrees along the chord length (0-1), the airflow angle of the leading edge of the blade root is 40-75 degrees, and the airflow angle of the trailing edge of the blade root is 10-30 degrees. The helix angle and the air flow angle of the blade tip and the blade root are kept consistent. The method adopts NACA series airfoil profile with the thickness of 5-15 percent.

when the distance between the radial section of the centrifugal impeller and the hub is 0.5B, the helix angle of the front edge and the airflow angle of the radial section are respectively 6 degrees and 24 degrees, the helix angle of the rear edge and the airflow angle are respectively 30 degrees and 11 degrees, wherein B is the span length of the centrifugal impeller blade;

Detailed description of the preferred embodiment 1

Aiming at the working conditions of the air pressurization system of the respirator, the pneumatic shapes of a centrifugal impeller, an interstage air guide wheel and an outlet air guide wheel with high pressure ratio and high isentropic efficiency are obtained by utilizing fluid dynamics simulation software CFD to carry out numerical simulation and geometric parameter optimization design.

The ratio of the area of the throat to the area of the inlet of the booster fan is preferably 1:1.15, the half cone angle of the inlet is 10 degrees, the length of the inlet is preferably 6mm, and the distance between the first-stage centrifugal impeller and the front section of the outer cover is 0.2 mm.

The booster fan has a length of 91mm and a diameter of 52 mm. The number of blades of the centrifugal impeller is 10, the diameter of the impeller is 41mm, and the height of an inlet of the impeller is 6.8 mm; the number of the interstage air guide impeller blades is 6, the diameter of the impeller is 52mm, the height of an inlet of the impeller is 14mm, the radius of the front edge of the impeller is 0.25mm, and the radius of the rear edge of the impeller is 0.1 mm. The number of outlet air guide impeller blades is 6, the diameter of the impeller is 42mm, the inlet height of the impeller is 6mm, the radius of the front edge of the impeller is 0.25mm, and the radius of the rear edge of the impeller is 0.1 mm.

The preferred value of the flow angle of the leading edge of the blade root of the centrifugal impeller is 20 degrees, and the preferred value of the flow angle of the trailing edge of the blade root is 10 degrees; the preferred value of the blade tip leading edge airflow angle is 40 degrees, and the preferred value of the blade root trailing edge airflow angle is 13 degrees

The preferable value of the blade root leading edge airflow angle of the interstage air guide impeller is 78 degrees, and the preferable value of the blade root trailing edge airflow is 0 degree. The helix angle and the air flow angle of the blade tip and the blade root are kept consistent.

The root leading edge flow angle is preferably 69 and the root trailing edge flow is preferably 20. The helix angle and the air flow angle of the blade tip and the blade root are kept consistent.

The thicknesses of the centrifugal impeller, the interstage air guide impeller and the outlet air guide impeller are preferably 15%, 10% and 10%.

Under the condition that the rotating speed of the brushless motor is 25000rpm, the total pressure ratio and the isentropic efficiency of the air pressurization system reach the maximum, the total pressure ratio of 1.033 times (the pressure rise is more than or equal to 3300Pa), the air mass flow rate of 2.4g/s, the air volume flow rate of 117L/s and the isentropic efficiency of 55 percent can be obtained, and the applicable temperature of the air is minus 10 ℃ to 50 ℃.

Test results show that under the condition that the rotating speed of the brushless motor is not less than 25000rpm, the total pressure ratio and the isentropic efficiency of the air pressurization system can be higher, the total pressure ratio is not less than 1.033, the isentropic efficiency is not less than 55%, and the technical requirements of the air pressurization system of the breathing machine can be completely met.

Compared with the existing air pressurization system of the respirator, the design of the invention is greatly improved. The supercharging impeller is designed in a centrifugal mode, a flow model of a supercharging system of the respirator is established by adopting an aerospace aerodynamic technology, pneumatic numerical simulation and optimization design are carried out on the centrifugal impeller on a high-performance large-scale super computer platform, geometric parameters and the number of blades of the impeller are determined, and a centrifugal impeller configuration with a higher pressure ratio is obtained. The invention adopts the one-stage air inlet channel in the shape of the square root, optimizes the inner appearance of the air inlet channel, combines the design with the centrifugal impeller, can greatly improve the flow efficiency, reduces the noise of the centrifugal impeller in the flow channel, and combines the design of the axial flow double rotors to ensure that the system total pressure ratio of the centrifugal impeller fan is large, the applicable temperature range is wide, the efficiency is high and the reliability is high.

The above description is only a preferred embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by using the contents of the present specification and the accompanying drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims

1. The utility model provides a two-stage centrifugal impeller fan for breathing machine air charge system which characterized in that: it comprises two opposing centrifugal impellers (3, 9).

2. The two-stage centrifugal impeller fan of claim 1, wherein: the device comprises a primary air inlet channel (1), an outer cover (2), a primary centrifugal impeller (3), a motor A (4), an integrated supporting end cover (5), a motor B (6), an interstage air guide impeller (7), a secondary air inlet channel (8), a secondary centrifugal impeller (9), an outlet air guide impeller (10) and a tail cover (11); the tail part of the primary air inlet channel (1) is arranged on the outer cover (2), the primary centrifugal impeller (3) is arranged on a front end shaft of the motor A (4), the integral supporting end cover (5) is arranged on the outer cover (2), and the motor A (4) and the motor B (6) are respectively arranged at two ends of the integral supporting end cover (5) and used for driving the impeller to rotate; the interstage guide air wheel (7) is installed on the motor B (6), the secondary air inlet channel (8) is installed on the interstage guide air wheel (7), the secondary centrifugal impeller (9) is installed on a tail section shaft of the motor B (6), the outlet guide air impeller (10) is installed on the tail cover (11), and the tail cover (11) is connected with the outer cover (2) and sealed.

3. A two-stage centrifugal impeller fan according to any of claims 1-2, wherein: the front end of the shaft of the motor A (4) drives the first-stage rotor centrifugal impeller (3) to suck air from the air inlet channel (1), the air is acted, dynamic pressure is increased, after the air is subjected to diffusion, the dynamic pressure is reduced, static pressure is increased, the air flows through an air channel and enters the interstage air guide impeller (7), and radial flow is changed into axial flow; then, the airflow enters the secondary air inlet channel (8) from the interstage air guide impeller (7), is sucked by the secondary centrifugal impeller (9), is subjected to secondary pressurization, increases dynamic pressure, reduces the dynamic pressure and increases static pressure after the air enters the outlet air guide impeller (10), the airflow changes from the radial direction to the axial direction again, and finally the airflow is ejected through an air outlet of the tail cover (11).

4. A two-stage centrifugal impeller fan according to any of claims 1 to 3, wherein: the primary air inlet channel (1) is in a V shape, and the area ratio of a throat to an inlet of the air inlet channel is 1.1-1.4; the half cone angle of the air inlet channel is 5-15 degrees, and the length of the air inlet channel is 5-10 mm; the first-stage centrifugal impeller (3) is a centrifugal booster impeller, and the number of blades is 8-14; the diameter of the centrifugal supercharging impeller is 38 mm-50 mm; the height is 5 mm-10 mm, the blades adopt NACA series airfoil profiles, and the thickness is 10% -30%; the radius of the front edge and the rear edge of the blade is 0.25 mm-1 mm; the helix angle of the blade root is 0-50 degrees along the chord length (0-1), the airflow angle of the leading edge of the blade root is 10-20 degrees, and the airflow angle of the trailing edge of the blade root is 0-15 degrees; the helix angle of the blade tip is 10-50 degrees along the chord length (0-1), the airflow angle of the leading edge of the blade tip is 30-50 degrees, and the airflow angle of the trailing edge of the blade tip is 5-20 degrees.

5. The two-stage centrifugal impeller fan for a respirator air plenum system of claim 4, wherein: the distance between the first-stage centrifugal impeller and the front section of the outer cover is 0.2 mm.

6. The two-stage centrifugal impeller fan for a respirator air plenum system of claim 4, wherein: the second-stage centrifugal impeller and the first-stage centrifugal impeller are in the same geometric configuration.

7. A two-stage centrifugal impeller fan according to any of claims 2 to 6, wherein: the interstage guide gas wheel (7) adopts a 90-degree spiral petal type design, and the number of blades is 6; the interstage air guide wheel (7) is a swirler, radial airflow is changed into axial airflow, the channel area of the interstage air guide wheel (7) is in a gradually increasing rule, so that the airflow enters the air guide wheel and then is subjected to speed reduction and pressure expansion, pressure loss caused by flow reversing is reduced, and the airflow enters a secondary air inlet channel; the height of the interstage air guide impeller (7) is 14 mm; the radius of the front edge of a blade of the interstage air guide impeller (7) is 0.25mm, the radius of the rear edge of the blade of the interstage air guide impeller (7) is 0.1mm, the optimal value of the helix angle of the blade root of the blade of the interstage air guide impeller (7) along the chord length (0-1) is 0-90 degrees, the helix angle and the airflow angle of a blade tip and the blade root are kept consistent, and the thickness of the blade tip and the blade root is 10% by adopting an NACA (aerovane) series;

the outlet air guide impeller (9) is designed in a 125-degree spiral petal type mode, the number of blades is 6, radial airflow is changed into axial airflow by the outlet air guide impeller (9), the channel area of the outlet air guide impeller (9) is in a gradually decreasing rule, so that the airflow is accelerated and discharged after entering the air guide impeller, the height of the outlet air guide impeller (9) is 5mm, the leading edge of the blades of the outlet air guide impeller (9) is 0.25mm, the radius of the trailing edge of the leading edge of the blades is 0.1mm, the helix angle of the root of the blades is 0-150 degrees along the chord length (0-1), the airflow angle of the leading edge of the blade root is 40-75 degrees, the airflow angle of the trailing edge of the blade root is 10-30 degrees, and the helix angle and the airflow angle of the blade root and the blade tip are kept consistent.