Impeller and ventricular assist device

Abstract

The application provides a kind of impeller and ventricular assist device, impeller includes hub and at least one fixed on the periphery of hub blade, hub includes import end and export end, blade includes action surface, the profile line of action surface includes the outer edge profile line away from hub, the end point of outer edge profile line near import end is profile line starting point, the end point of outer edge profile line near export end is profile line terminal point;Outer edge profile line is smooth spatial curve, the curvature of outer edge profile line along the hub axial gradually decreases in the process from profile line starting point to profile line terminal point, simultaneously, the curvature variation rate of outer edge profile line along the hub axial also gradually decreases.The impeller and ventricular assist device provided by the application make blood flow smoothly when flowing through the action surface of blade, the change of flow velocity is gentle and the distribution is uniform, which helps to improve the hydraulic performance that can be achieved by impeller, reduce the flow loss of blood, reduce blood injury and avoid the formation of flow dead zone.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of medical devices, in particular to a impeller and a ventricular assist device. BACKGROUND

[0002] A percutaneously implantable artificial ventricular assist device (PLVAD, hereinafter referred to as a catheter pump) is a miniaturized blood pumping device that can be introduced into the heart and can be configured to assist or replace the natural heart function by circulating or continuous pumping of blood to provide blood flow dynamic support for cardiogenic shock and acute heart failure. The blood flow dynamics of the catheter pump is derived from the high-speed rotation of the impeller, and the structural design of the impeller has an important influence on the hydraulic performance and hemolysis performance of the catheter pump. SUMMARY

[0003] Therefore, the present application aims to provide an impeller, which comprises a hub and at least one blade fixed to the outer periphery of the hub, the hub comprises an inlet end and an outlet end, the blade comprises an action surface, the profile line of the action surface comprises an outer edge profile line away from the hub, the end point of the outer edge profile line close to the inlet end is a profile line starting point, and the end point of the outer edge profile line close to the outlet end is a profile line ending point; the outer edge profile line is a smooth space curve, and the curvature of the outer edge profile line along the axial direction of the hub gradually decreases from the profile line starting point to the profile line ending point, and the rate of change of the curvature of the outer edge profile line along the axial direction of the hub also gradually decreases.

[0004] Optionally, the angle between the tangent line of the profile line starting point and the tangential velocity is an inlet angle of the outer edge profile line; the relative velocity of the profile line starting point is the resultant velocity of the axial velocity and the tangential velocity of the profile line starting point, and the angle between the relative velocity of the profile line starting point and the tangential velocity is an inlet installation angle of the outer edge profile line, and the inlet angle is greater than the inlet installation angle.

[0005] Optionally, the angle difference between the inlet angle and the inlet installation angle is not greater than 5°.

[0006] Optionally, the inlet installation angle is calculated by the following formula:

[0007]

[0008] In the formula, a m is the inlet installation angle, V a is the axial velocity of the profile line starting point, and V t is the tangential velocity of the profile line starting point.

[0009] The axial velocity of the profile line starting point is calculated by the following formula:

[0010]

[0011] In the formula, Q is a preset flow rate, A is a cross-sectional area of a pipe hole of a conduit for installing the impeller, and D is an inner diameter of the conduit.

[0012] The tangential velocity of the start point of the profile is calculated by the following formula:

[0013]

[0014] In the formula, ω is a preset rotating speed of the blade.

[0015] Optionally, the inlet angle is 25° to 35°.

[0016] Optionally, the outer edge profile is a spiral curve with gradually changing Gaussian curvature, and the formula is as follows:

[0017]

[0018]

[0019] Optionally, an angle between an axial plane where the start point of the profile is located and an axial plane where the end point of the profile is located is a blade deflection angle, and the blade deflection angle is 90° to 150°.

[0020] Optionally, the profile of the action surface further includes an inlet edge line intersecting the start point of the profile; when the impeller is projected along an axial direction of the hub, an angle between the inlet edge line and an axial direction of the start point of the profile is a tangential forward sweep angle, and the tangential forward sweep angle is 2° to 8°.

[0021] Optionally, the profile of the action surface further includes an inlet edge line intersecting the start point of the profile; when the impeller is projected along a radial direction of the hub, an angle between the inlet edge line and a horizontal line is an axial forward sweep angle, and the axial forward sweep angle is 10° to 26°.

[0022] Optionally, in the same radial cross section of the impeller, a ratio between the outer diameter of the blade and the outer diameter of the hub is 1.25 to 3.25.

[0023] Optionally, along the axial direction of the hub, a ratio between a length of the blade and a length of the hub is 0.86 to 0.87, and the end point of the profile is close to the outlet end.

[0024] Based on the same inventive concept, the application further provides a ventricular assist device, comprising a conduit and the impeller arranged in the conduit.

[0025] From the above, it can be seen that the impeller and the ventricular assist device provided by the application have the following advantages: the outer edge profile of the action surface smoothly transitions from the profile starting point to the profile ending point along the axial direction, and the curvature and the rate of change of curvature of the outer edge profile along the hub axial direction are gradually reduced, so that the blood flows smoothly, the flow velocity changes gently and is uniformly distributed when flowing through the blade action surface, which helps to improve the hydraulic performance that the impeller can achieve, reduce the flow loss of the blood, reduce the blood injury, and avoid the formation of flow dead zones. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the application or the related art, the following will briefly introduce the drawings needed to be used in the embodiments or the related art description. Obviously, the drawings in the following description are only embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0027] Figure 1 It is a front view of the impeller of the embodiment of the application;

[0028] Figure 2 It is a side view of the impeller of the embodiment of the application;

[0029] Figure 3 It is a top view of the impeller of the embodiment of the application;

[0030] Figure 4 It is a comparison bar chart of the differential pressure of the impeller of the embodiment of the application with the inflow attack angle of 0° and 5° respectively;

[0031] Figure 5 It is a comparison bar chart of the average scalar shear stress of the impeller of the embodiment of the application with the inflow attack angle of 0° and 5° respectively;

[0032] Figure 6 It is a comparison bar chart of the hemolysis index of the impeller of the embodiment of the application with the inflow attack angle of 0° and 5° respectively;

[0033] Figure 7 It is a comparison chart of the three-dimensional flow field of the impeller of the embodiment of the application with the inflow attack angle of 0° and 5° respectively;

[0034] Figure 8 It is a comparison chart of the radial cross-sectional flow field of the impeller of the embodiment of the application with the inflow attack angle of 0° and 5° respectively;

[0035] Figure 9 It is a comparison chart of the radial cross-sectional pressure of the impeller of the embodiment of the application with the inflow attack angle of 0° and 5° respectively;

[0036] Figure 10Radial cross-section vortex ratio comparison chart for two structures of impeller of the embodiment of the present application with 0° and 5° of inlet flow attack angle respectively;

[0037] Figure 11 Radial cross-section scalar shear stress ratio comparison chart for two structures of impeller of the embodiment of the present application with 0° and 5° of inlet flow attack angle respectively;

[0038] Figure 12 Radial cross-section hemolysis index ratio comparison chart for two structures of impeller of the embodiment of the present application with 0° and 5° of inlet flow attack angle respectively;

[0039] Figure 13 Another radial cross-section flow field comparison chart for two structures of impeller of the embodiment of the present application with 0° and 5° of inlet flow attack angle respectively;

[0040] Figure 14 Another radial cross-section pressure ratio comparison chart for two structures of impeller of the embodiment of the present application with 0° and 5° of inlet flow attack angle respectively;

[0041] Figure 15 Another radial cross-section vortex ratio comparison chart for two structures of impeller of the embodiment of the present application with 0° and 5° of inlet flow attack angle respectively;

[0042] Figure 16 Another radial cross-section scalar shear stress ratio comparison chart for two structures of impeller of the embodiment of the present application with 0° and 5° of inlet flow attack angle respectively;

[0043] Figure 17 Another radial cross-section hemolysis index ratio comparison chart for two structures of impeller of the embodiment of the present application with 0° and 5° of inlet flow attack angle respectively;

[0044] Figure 18 Pressure difference comparison bar chart for three structures of impeller of the embodiment of the present application with 90°, 110° and 180° of blade deflection angle respectively;

[0045] Figure 19 Average scalar shear stress comparison bar chart for three structures of impeller of the embodiment of the present application with 90°, 110° and 180° of blade deflection angle respectively;

[0046] Figure 20 Hemolysis index comparison bar chart for three structures of impeller of the embodiment of the present application with 90°, 110° and 180° of blade deflection angle respectively;

[0047] Figure 21 Three-dimensional flow field comparison chart for three structures of impeller of the embodiment of the present application with 90°, 110° and 180° of blade deflection angle respectively;

[0048] Figure 22Radial cross-section flow field comparison chart of three structures of blade deflection angle 90°, 110° and 180° of the impeller of the embodiment of the present application;

[0049] Figure 23 Radial cross-section pressure comparison chart of three structures of blade deflection angle 90°, 110° and 180° of the impeller of the embodiment of the present application;

[0050] Figure 24 Radial cross-section vortex comparison chart of three structures of blade deflection angle 90°, 110° and 180° of the impeller of the embodiment of the present application;

[0051] Figure 25 Radial cross-section scalar shear stress comparison chart of three structures of blade deflection angle 90°, 110° and 180° of the impeller of the embodiment of the present application;

[0052] Figure 26 Radial cross-section hemolysis index comparison chart of three structures of blade deflection angle 90°, 110° and 180° of the impeller of the embodiment of the present application;

[0053] Figure 27 Another radial cross-section flow field comparison chart of three structures of blade deflection angle 90°, 110° and 180° of the impeller of the embodiment of the present application;

[0054] Figure 28 Another radial cross-section pressure comparison chart of three structures of blade deflection angle 90°, 110° and 180° of the impeller of the embodiment of the present application;

[0055] Figure 29 Another radial cross-section vortex comparison chart of three structures of blade deflection angle 90°, 110° and 180° of the impeller of the embodiment of the present application;

[0056] Figure 30 Another radial cross-section scalar shear stress comparison chart of three structures of blade deflection angle 90°, 110° and 180° of the impeller of the embodiment of the present application;

[0057] Figure 31 Another radial cross-section hemolysis index comparison chart of three structures of blade deflection angle 90°, 110° and 180° of the impeller of the embodiment of the present application.

[0058] Explanation of reference numerals:

[0059] 1, hub; 11, inlet end; 12, outlet end;

[0060] 2 blade; 21 action surface; 211 outer edge line; 212 inlet edge line; 213 outlet edge line; 214 line start point; 215 line end point; 216 hub line. DETAILED DESCRIPTION

[0061] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to specific embodiments and drawings.

[0062] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application should be understood as the common meanings understood by those skilled in the art to which the embodiments of the present application belong. The terms "first", "second" and similar terms used in the embodiments of the present application do not represent any order, number or importance, but are only used to distinguish different components. The terms "include" or "contain" and similar terms mean that the elements or objects before the terms encompass the elements or objects listed after the terms and their equivalents, and do not exclude other elements or objects. The terms "connect" or "connected" and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms "upper", "lower", "left", "right" and the like are only used to represent relative positional relationships, and when the absolute positions of the described objects change, the relative positional relationships may also change accordingly.

[0063] According to the content of the foregoing background section, it can be known that the hydraulic performance and hemolysis performance of the conduit pump are closely related to the structure of the impeller.

[0064] Hydraulic performance refers to the flow rate and head that the conduit pump can achieve under the target volume and working conditions.

[0065] In order to enable the conduit pump to meet the blood circulation needs of different patients, according to the blood output per minute, the conduit pump can have multiple types, such as 2.5L / min, 3.5L / min, 5.0L / min type conduit pump.

[0066] Hemolysis refers to the phenomenon that red blood cells in the blood burst, and hemoglobin in the red blood cells spills out and dissolves in the blood. Hemolysis can cause changes in the morphology and biochemical characteristics of red blood cells, shorten the life span, and even completely rupture, thereby reducing the ability of red blood cells to transport oxygen to tissues and organs. In addition, after hemolysis, the concentration of free hemoglobin in plasma increases, and the excess free hemoglobin needs to be excreted through the kidneys, which can cause damage to kidney function and multiple organ failure.

[0067] Therefore, when pumping blood of a medical subject, it is very important to prevent hemolysis of the pumped blood. If the blood is hemolyzed during pumping, it will endanger the life safety of the medical subject.

[0068] In order to ensure the safety of the catheter pump, the hemolysis performance needs to be considered. The hemolysis performance refers to the probability of hemolysis caused by blood cell damage after the blood flows through the catheter pump.

[0069] In order to meet the requirements of hydraulic performance and hemolysis performance, some related technology adopts a micro axial flow structure for the impeller.

[0070] The applicant found that due to the particularity of the use scene of the catheter pump, there are still two key technical problems in the design and manufacture of the impeller: firstly, in order to reduce the influence of implantation operation on the normal physiology of the human body, the outer diameter of the impeller is limited to within 7mm suitable for passing through the blood vessel, which strictly limits the volume of the impeller and the blades on the impeller, and further causes the hydraulic performance of the impeller to be difficult to meet the standards; secondly, in order to meet the pressure value required by the human blood circulation, the pump blood performance needs to be improved by increasing the rotation speed of the impeller, but the high-speed rotation of the impeller will increase the shear stress of the blood flow field, causing the blood cells to break, and further causing mechanical hemolysis.

[0071] Therefore, the structure of the catheter pump impeller needs to consider both the hydraulic performance and the hemolysis performance. The consideration conditions for the hydraulic performance mainly include the output flow and the pressure difference between the inlet end and the outlet end of the catheter pump, and the consideration conditions for the hemolysis performance mainly include the shear stress of the blood in the pumping process and the flow stability of the blood. Through the optimization and improvement of the structure of the impeller, the hydraulic performance is improved, and the blood damage caused by hemolysis is reduced.

[0072] Therefore, as shown in Figure 1 and Figure 2 The embodiment of the present application provides an impeller, which comprises a hub 1 and at least one blade 2 fixed to the outer periphery of the hub 1, the hub 1 comprises an inlet end 11 and an outlet end 12; the blade 2 comprises an action surface 21, the profile line of the action surface 21 comprises an outer edge profile line 211 away from the hub 1, the end point of the outer edge profile line 211 close to the inlet end 11 is a profile starting point 214, and the end point of the outer edge profile line 211 close to the outlet end 12 is a profile ending point 215; the outer edge profile line 211 is a smooth space curve, and the curvature of the outer edge profile line 211 along the axial direction of the hub 1 gradually decreases from the profile starting point 214 to the profile ending point 215, and the curvature change rate of the outer edge profile line 211 along the axial direction of the hub 1 also gradually decreases.

[0073] When the blade 2 rotates with the hub 1, the action surface 21 of the blade 2 produces a pumping effect on the blood, so the structure of the action surface 21 plays a key role in the overall performance of the impeller and even the catheter pump, and when the profile line of the action surface 21 is determined, the overall curved surface structure of the action surface 21 can be determined.

[0074] The contour line of the working surface 21 includes the hub profile line 216 connected to the outer periphery of the hub 1, which, together with the outer edge profile line 211, constitutes the main streamline structure of the blade 2. The connecting line between the starting point of the hub profile line 216 (i.e., the end point of the hub profile line 216 near the inlet end 11) and the starting point of the outer edge profile line 211 (i.e., the end point of the outer edge profile line 211 near the inlet end 11) is the inlet edge line 212. Similarly, the connecting line between the ending point of the hub profile line 216 (i.e., the end point of the hub profile line 216 near the outlet end 12) and the ending point of the outer edge profile line 211 (i.e., the end point of the outer edge profile line 211 near the outlet end 12) is the outlet edge line 213.

[0075] The outer edge profile 211 is a smooth spatial curve, indicating that the working surface 21 smoothly transitions from the side near the inlet end 11 to the side near the outlet end. As blood flows smoothly along the curved structure of the working surface 21 from the impeller inlet to the outlet, it helps to reduce flow loss. At the same time, the gradual change in blood velocity and the uniform distribution of blood as it flows along the working surface 21 help to reduce flow dead zones and reduce blood damage.

[0076] The greater the curvature of the outer edge profile 211 along the axial direction of the hub 1, the greater the degree of curvature of the outer edge profile 211. In other words, the greater the degree to which the outer edge profile 211 deviates from the axial line of the hub 1.

[0077] The outer edge profile 211 has a larger rate of curvature change near the starting point 214, which allows blood to rotate tangentially along the outer edge profile 211 at the impeller inlet and flow into the flow channel formed by the blades 2. This helps reduce flow disturbance and avoid flow dead zones and blood damage. As the outer edge profile 211 extends towards the impeller outlet, the rate of curvature change decreases linearly. At the end point 215, both the curvature and the rate of curvature change of the outer edge profile 211 along the hub 1 axis are minimized. This maximizes the pumping work of the blades 2 on the blood at the impeller outlet, which helps increase the flow rate and the pressure difference between the impeller inlet and outlet of 2.

[0078] The impeller provided in this embodiment has an outer edge profile 211 of its working surface 21 that smoothly transitions from the beginning point 214 to the end point 215 of the profile along the axial direction. The curvature and rate of change of curvature of the outer edge profile 211 along the axial direction of the hub 1 gradually decrease, so that blood flows smoothly, the flow velocity changes gently and the distribution is uniform when it flows through the working surface 21 of the blade 2. This helps to improve the hydraulic performance that the impeller can achieve, reduce blood flow loss, reduce blood damage and avoid the formation of flow dead zones.

[0079] like Figure 1 As shown, in some embodiments, the tangent at the starting point 214 of the profile ( Figure 1 (middle dashed line) and tangential velocity V t The included angle is the included angle α at the inlet of the outer edge profile 211; the axial velocity V at the starting point of the profile 214 aand the tangential velocity V t The relative velocity V of the resultant velocity is the relative velocity V of the profile starting point 214 and the tangential velocity V t The angle between the relative velocity V and the tangent of the profile starting point 214 is the inlet installation angle a of the outer edge profile 211 m The inlet angle a is greater than the inlet installation angle a m .

[0080] When the inlet angle a is greater than the inlet installation angle a m , an angle difference is generated between the two, which is the angle a between the relative velocity V and the tangent of the profile starting point 214, and the angle a is also called the inlet attack angle or the inlet angle of attack.

[0081] Under the condition of low-speed blood flow, the inlet attack angle can inhibit the flow separation of blood when flowing through the action surface 21, reduce the inlet flow loss of blood when entering the impeller, increase the hydraulic performance, and also help to reduce blood damage.

[0082] In some embodiments, the angle difference between the inlet angle a and the inlet installation angle a m is not greater than 5°.

[0083] In the typical but non-limiting embodiments of the present application, the angle of the installation angle a m is 0°, 1°, 2°, 3°, 4° or 5°.

[0084] As Figures 4 to 17 , two impeller structures with inlet attack angles of 0° and 5° are selected for simulation experiments to compare the hydraulic performance and hemolysis performance of the two impeller structures.

[0085] As Figure 4 can be seen, in the structure with an inlet attack angle of 5°, the pressure difference between the inlet and the outlet of the impeller is significantly improved compared to the impeller structure with an inlet attack angle of 0°, and correspondingly, the impeller in this structure can achieve a larger head. Compared with the structure with an inlet attack angle of 0°, the impeller with an inlet attack angle of 5° has better hydraulic performance.

[0086] As Figure 5 can be seen, in the structure with an inlet attack angle of 5°, the average scalar shear stress generated by the impeller during rotation is significantly reduced compared to the impeller structure with an inlet attack angle of 0°. The effect of lower average scalar shear stress is also reflected in Figure 6 , it can be seen that the hemolysis index in the structure with an inlet attack angle of 5° is significantly reduced compared to the structure with an inlet attack angle of 0°, indicating that the impeller structure with an inlet attack angle of 5° can ensure that the pumped blood has better physiological indicators and has better hemolysis performance.

[0087] On the basis of the above data, by Figures 7 to 17The difference in hydraulic performance and hemolysis performance between the two impeller structures with 0° and 5° inlet attack angle can be more intuitively shown.

[0088] Figure 7 The three-dimensional flow field comparison chart of the two impeller structures is shown in the figure, and the arrows of different color depths represent the speed value of the fluid flowing through the impeller. It can be seen that the blood (i.e. blood) has the same state before entering the impeller inlet, and flow separation occurs when the inlet attack angle of the structure is 0°, while the inlet attack angle of the structure is 5°. The flow separation does not occur. Compared with the structure with 0° inlet attack angle, the impeller with 5° inlet attack angle has better hydraulic performance.

[0089] Figure 8 The flow field comparison of the radial section of the two impeller structures is also shown by arrows of different colors representing the speed value of the blood flowing through the impeller. It can also be seen that in the structure with 0° inlet attack angle, the blood flowing out of the impeller separates, and the blood also appears turbulent. In the structure with 5° inlet attack angle, the blood flow is more stable and uniform, and has better hydraulic performance.

[0090] Figure 9 The radial section pressure comparison of the two impeller structures is shown in the figure, and different colors are used to represent the pressure distribution of the fluid flowing through the impeller. It can be seen that in the structure with 5° inlet attack angle, the pressure at the outlet of the impeller is lower, and the pressure difference between the inlet and outlet of the impeller is more obvious. Compared with the structure with 0° inlet attack angle, the impeller with 5° inlet attack angle has better hydraulic performance.

[0091] Figure 10 The radial section vortex comparison of the two impeller structures is shown in the figure, and different colors are used to represent the vortex distribution of the blood flowing through the impeller. It can be seen that in the structure with 5° inlet attack angle, the vortex is more uniformly distributed around the impeller, avoiding vortex concentration, so that the blood flowing through the impeller is more stable, which helps to reduce flow loss. Compared with the structure with 0° inlet attack angle, the impeller with 5° inlet attack angle has better hydraulic performance.

[0092] Figure 11 The radial section scalar shear stress comparison of the two impeller structures is shown in the figure, and different colors are used to represent the distribution of the scalar shear stress of the fluid flowing through the impeller. It can be seen that in the structure with 5° inlet attack angle, the scalar shear stress is relatively small, especially at the outlet of the impeller.

[0093] Figure 12The radial cross-section hemolysis index of the two impeller structures is shown in the figure, and different colors are used to represent the distribution of the hemolysis index of the fluid flowing through the impeller. Corresponding to the scalar shear stress, the hemolysis index is lower under the structure with an inlet flow attack angle of 5°, especially after the blood flows out of the impeller. Compared with the structure with an inlet flow attack angle of 0°, the impeller with an inlet flow attack angle of 5° has better hemolysis performance.

[0094] Figures 13 to 17 is another radial cross-section of the impeller selected for the above Figures 8 to 12 The simulation experiment is performed to further verify the hydraulic performance and hemolysis performance of the impeller under the two impeller structures with an inlet flow attack angle of 0° and an inlet flow attack angle of 5°. Figures 13 to 17 The experimental results shown are the same as Figures 8 to 12 and will not be described here again.

[0095] From the above simulation experiment, it can be seen that compared with the structure with an inlet flow attack angle of 0°, the impeller with an inlet flow attack angle of 5° can achieve higher hydraulic performance and reduce the hemolysis of the pumped blood.

[0096] In some embodiments, the inlet included angle α of the outer edge profile line 211 is 25° to 35°.

[0097] In a typical but non-limiting embodiment of the present application, the inlet included angle α of the outer edge profile line 211 is 25°, 26°, 27°, 28°, 29°, 30°, 31°, 32°, 33°, 34° or 35°.

[0098] Optionally, the inlet installation angle a m is calculated by the following formula:

[0099]

[0100] The formula for calculating the axial velocity V a of the profile starting point 214 is:

[0101]

[0102] In the formula, Q is the preset flow rate, A is the pipe cross-sectional area of the conduit pump at the installation position of the impeller, and D is the inner diameter of the conduit pump at the installation position of the impeller.

[0103] The formula for calculating the tangential velocity V t of the profile starting point 214 is:

[0104]

[0105] In the formula, ω is the preset rotational speed of the blade 2.

[0106] The formula for calculating the inlet included angle a of the outer edge profile 211 is:

[0107] a = a + a m

[0108] Taking the preset flow rate Q as 5 L / min, the inner diameter D of the conduit pump as 5 mm, and the preset rotating speed w as 35,000 RPM (revolutions per minute) as an example, the calculation of the inlet included angle a is described as follows:

[0109]

[0110]

[0111]

[0112] The obtained result 0.4338 rad is in the radian system, which is converted into an angle value of about 25°, i.e., the installation angle is 25°.

[0113] According to the simulation experiment of the aforementioned inlet attack angle, the angle value of the inlet attack angle is taken as 5°, and then

[0114] a = a + a m ≈ 30°

[0115] In some embodiments, the outer edge profile 211 is a Gaussian curvature gradually changing spiral curve.

[0116] Alternatively, the formula of the outer edge profile 211 is:

[0117]

[0118]

[0119] As can be seen from the above formula, the outer edge profile 211 has the characteristics of continuous derivability along the axial and tangential directions, which makes the action surface 21 smoothly transition from the inlet side to the outlet side.

[0120] The starting point of the outer edge profile 211 corresponds to the point where z = 0 in the above formula, and as the value of z gradually increases (i.e., from the profile starting point 214 to the profile ending point 215), the curvature and the rate of change of curvature of the outer edge profile 211 along the axial direction of the hub 1 gradually decrease.

[0121] In addition, the angle value of the inlet included angle a can also be calculated by the aforementioned curve formula of the outer edge profile 211, and the specific process is as follows:

[0122] First, the curve formula is differentiated:

[0123]

[0124] Then, the obtained result is subjected to an inverse tangent operation:

[0125]

[0126] The angle is the angle between the tangent of the profile starting point 214 and the z-axis direction, as shown in the figure. Figure 1 The angle of the inlet angle a can be calculated as 30°

[0127] As shown in the figure, Figure 3 In some embodiments, the angle between the axial plane where the profile starting point 214 is located and the axial plane where the profile ending point 215 is located is the blade deflection angle θ, and the angle of the blade deflection angle θ is 90° to 150°.

[0128] In the typical but non-limiting embodiments of the present application, the angle of the blade deflection angle θ is 90°, 95°, 100°, 105°, 110°, 115°, 120°, 125°, 130°, 135°, 140°, 145°, 150°.

[0129] The axial plane where the profile starting point 214 is located represents the plane where the profile starting point 214 and the center axis of the hub 1 are located together, and since this plane is defined by a straight line (i.e. the center axis of the hub 1) and a point outside the straight line (the profile starting point 214), it is uniquely determined. Similarly, the axial plane where the profile ending point 215 is located represents the plane where the profile starting point 214 and the center axis of the hub 1 are located together, and it is also uniquely determined.

[0130] In combination with the figure, Figure 3 The blade deflection angle θ can be more intuitively understood as the angle between the line connecting the profile starting point 214 and the hub 1 axis and the line connecting the profile ending point 215 and the hub 1 axis in the top view of the impeller. The size of the blade deflection angle θ reflects the length of each blade 2 extending along the circumference of the hub 1.

[0131] As shown in the figure, Figures 18 to 31 Three impeller structures with blade deflection angles θ of 90°, 110° and 180° were selected for simulation experiments to compare the hydraulic performance and hemolysis performance of the three impeller structures. The three impeller models used in the simulation experiments all have two blades 2 evenly distributed.

[0132] As can be seen from the figure, Figure 18 It can be seen that in the structure with a blade deflection angle θ of 110°, the pressure difference between the inlet and the outlet of the impeller is the highest, and correspondingly, the impeller can achieve a larger head in this structure. The structure with a blade deflection angle θ of 90° is second, and the structure with a blade deflection angle θ of 180° produces a negative pressure difference. Therefore, compared to the structures with blade deflection angles θ of 90° and 180°, the impeller with a blade deflection angle θ of 110° can achieve better hydraulic performance.

[0133] As can be seen from the figure,Figure 19 It can be seen that in the structure of the blade deflection angle θ of 110°, the average scalar shear stress generated by the impeller during rotation is significantly lower. The structure of the blade deflection angle θ of 180° is second, and the structure of the blade deflection angle θ of 90° generates the highest average scalar shear stress. The effect of lower average scalar shear stress is also reflected in Figure 20 It can be seen that in the structure of the blade deflection angle θ of 110°, the hemolysis index is lower than the other two structures, indicating that the impeller can ensure that the pumped blood has better physiological indicators. In the structure of the blade deflection angle θ of 180°, the hemolysis index is slightly higher than that of the structure of the blade deflection angle θ of 110°, and the two structures are almost equivalent. In the structure of the blade deflection angle θ of 90°, the hemolysis index increases significantly.

[0134] On the basis of the above data, by Figures 21 to 31 The difference in hydraulic performance and hemolysis performance of the three impellers when the blade deflection angle θ is 90°, 110° and 180° can be more intuitively displayed.

[0135] Figure 21 is a three-dimensional flow field comparison diagram of the three impeller structures. Different color depths of arrows in the figure represent the speed value of the fluid when flowing through the impeller. It can be seen that the blood (i.e. blood) has the same state before entering the impeller inlet. In the structure of the blade deflection angle θ of 110°, the blood flow velocity changes more smoothly and uniformly during the flow through the impeller; while in the structure of the blade deflection angle θ of 90°, the blood flow velocity will suddenly increase at the inlet side of blade 2, and at the same time, the blood also produces more turbulence during the flow through the impeller; in the structure of the blade deflection angle θ of 180°, the blood flow velocity will suddenly decrease at the outlet side of blade 2, and at the same time, the blood also produces turbulence during the flow through the impeller, but better than the structure of the blade deflection angle θ of 90°.

[0136] Figure 22 is a radial cross-sectional flow field comparison of the three impeller structures, which also uses arrows of different colors to represent the speed value of the blood when flowing through the impeller. In the structure of the blade deflection angle θ of 110°, the blood flow velocity changes more smoothly and uniformly when flowing through the impeller, and has better hydraulic performance than the other two structures.

[0137] Figure 23 is a radial cross-sectional pressure comparison of the three impeller structures, which uses different colors to represent the distribution of the pressure of the blood when flowing through the impeller. It can be seen that in the structure of the blade deflection angle θ of 110°, the impeller has a more obvious pressure difference between the inlet and the outlet. Compared with the other two structures, the impeller with the blade deflection angle θ of 110° has better hydraulic performance.

[0138] Figure 24The radial cross-section vorticity of the three impeller structures is shown in the figure, and different colors are used to represent the distribution of the vorticity of the blood flowing through the impeller. It can be seen that in the structure with a blade deflection angle θ of 110°, the vorticity generated by the blood flowing through the impeller is the least, and the distribution is more uniform, avoiding the concentration of vortexes, so that the blood flowing through the impeller is more stable, which helps to reduce the flow loss. In the structure with a blade deflection angle θ of 180°, the vorticity generated by the blood is more, and in the structure with a blade deflection angle θ of 90°, the vorticity generated by the blood is the most. Compared with the other two structures, the impeller with a blade deflection angle θ of 110° has better hydraulic performance.

[0139] Figure 25 The radial cross-section scalar shear stress of the three impeller structures is shown in the figure, and different colors are used to represent the distribution of the scalar shear stress of the blood flowing through the impeller. It can be seen that in the structure with a blade deflection angle θ of 110°, the scalar shear stress received by the blood flowing through the impeller is the least, especially at the outlet of the impeller. In the structure with a blade deflection angle θ of 180°, the scalar shear stress received by the blood is more, and in the structure with a blade deflection angle θ of 90°, the scalar shear stress received by the blood is the most.

[0140] Figure 26 The radial cross-section hemolysis index of the three impeller structures is shown in the figure, and different colors are used to represent the distribution of the hemolysis index of the fluid flowing through the impeller. Corresponding to the scalar shear stress, in the structure with a blade deflection angle θ of 110°, the hemolysis index of the blood flowing through the impeller and flowing out of the impeller is the lowest compared with the other two structures. In the structure with a blade deflection angle θ of 180°, the hemolysis index is higher than that in the structure with a blade deflection angle θ of 110°, and in the structure with a blade deflection angle θ of 90°, the hemolysis index is the highest. Compared with the other two structures, the impeller with a blade deflection angle θ of 110° has better hemolysis performance.

[0141] Figures 27 to 31 Another radial cross-section of the impeller is selected for the above Figures 22 to 26 The simulation experiment is carried out in order to further verify the water conservancy performance and hemolysis performance of the impeller in the three structures with a blade deflection angle θ of 90°, 110° and 180°. Figures 27 to 31 The experimental results shown are the same as Figures 22 to 26 and will not be described here.

[0142] Through the above simulation experiment, it can be seen that compared with the structures with a blade deflection angle θ of 90° and 180°, the impeller with a blade deflection angle θ of 110° can achieve higher hydraulic performance and reduce the hemolysis of the pumped blood.

[0143] As Figure 3As shown, in some embodiments, when the impeller is projected along the axial direction of the hub 1, the radial angle between the inlet edge line 212 and the profile starting point 214 is the tangential sweep angle β, and the angle of the tangential sweep angle β is 2° to 8°.

[0144] In a typical but non-limiting embodiment of this application, the tangential sweep angle β is 2°, 3°, 4°, 5°, 6°, 7° or 8°.

[0145] like Figure 3 When blood enters the impeller inlet, the forward sweep angle β can increase the tangential velocity V. t A velocity component V1 is generated towards the central axis of hub 1. This velocity component V1 causes the blood to converge towards hub 1 during the rotating flow from the impeller inlet to the impeller outlet, thereby reducing the shear stress on the blood and preventing the generation of secondary flow, making the blood flow more stable.

[0146] Secondary flow refers to the deviation of blood along the radial direction of hub 1 during its flow due to the action of lateral forces (i.e., the radial force of hub 1). Secondary flow is the flow of a medium superimposed on the mainstream (the flow of blood along the axial direction of hub 1).

[0147] In addition to lateral forces, separation flows and vortices can also induce corresponding secondary flows.

[0148] In the impeller of this embodiment, because the blades 2 have a tangential sweep angle β, the blood generates a component velocity V1 towards the central axis of the hub 1 as it flows through the impeller. This component velocity V1 can have a certain converging effect on the blood, keeping it flowing around the circumference of the hub 1 and forming a stable flow field. This effectively avoids secondary flow of blood under the influence of lateral forces or separated flows, helps to reduce blood flow loss, improves the hydraulic performance of the impeller, and reduces damage to the blood, giving the impeller of this embodiment better hemolytic properties.

[0149] like Figure 2 As shown, in some embodiments, when the impeller is projected radially along the hub 1, the angle between the inlet edge line 212 and the horizontal line is the axial sweep angle γ, and the angle of the axial sweep angle γ is 10° to 26°.

[0150] In a typical but non-limiting embodiment of this application, the axial sweep angle γ is 10°, 11°, 12°, 13°, 14°, 15°, 16°, 17°, 18°, 19°, 20°, 21°, 22°, 23°, 24°, 25° or 26°.

[0151] like Figure 2 When blood enters the impeller inlet, the axial forward sweep angle γ can increase the axial velocity V. aThe component velocity V2 toward the central axis of the hub 1 is generated. The component velocity V2 can make the blood flow toward the hub 1 during the rotation of the blood from the impeller inlet to the impeller outlet, thereby reducing the shear stress of the blood and avoiding the generation of secondary flow, and making the blood flow more stable.

[0152] In the impeller of the embodiment, the blade 2 has the structure of the axial forward sweep angle γ, which can generate the component velocity V2 toward the central axis of the hub 1 during the blood flow through the impeller. The component velocity V2 and the component velocity V1 generated due to the tangential forward sweep angle β can jointly generate a certain convergence effect on the blood, so that the blood can flow along the circumference of the hub 1 and form a stable flow field. The generation of secondary flow due to the influence of the transverse force or the separation flow can be effectively avoided, which can help to reduce the flow loss of the blood, improve the hydraulic performance of the impeller, reduce the damage to the blood, and make the impeller of the embodiment have better hemolysis performance.

[0153] As shown in FIGS. Figure 1 and Figure 2 In some embodiments, the outer diameter of the hub 1 gradually increases from the inlet end 11 to the outlet end 12, and the inlet end 11 of the hub 1 has a smooth top structure.

[0154] Optionally, the inlet end 11 can have a spherical dome or a top structure of an approximately spherical dome obtained by rounding the outer edge of a cylinder.

[0155] The inlet end 11 has a spherical dome or an approximately spherical structure, which can help to reduce the resistance of the blood when the blood flows through the inlet end 11. At the same time, the generation of turbulent flow can be reduced, the blood flow can be more stable, and the flow loss and the generation of hemolysis can be reduced.

[0156] In some embodiments, in the same radial section of the impeller, the ratio of the outer diameter of the blade 2 to the outer diameter of the hub 1 is 1.25 to 3.25.

[0157] Optionally, in the impeller of the embodiment, the outer diameter of the hub 1 gradually increases from the inlet end 11 to the outlet end 12, and the outer diameter of the blade 2 remains unchanged. Therefore, the hub ratio gradually decreases from the start point 214 of the profile line to the end point 215 of the profile line.

[0158] In some embodiments, along the axial direction of the hub 1, the ratio of the length of the blade 2 to the length of the hub 1 is 0.86 to 0.87, and the end point 215 of the profile line is close to the outlet end 12.

[0159] In some embodiments, the installation angle of the outer edge profile line 211 is different from the installation angle of the hub profile line 216 at the same axial position, which makes the blade 2 a twisted blade. The twisted blade can help the blood to adhere to the impeller, increase the hydraulic performance of the impeller, and reduce the generation of special flow structures.

[0160] In some embodiments, the blade 2 has a uniform thickness.

[0161] Optionally, the intersection of the inlet side and the outer edge side of the blade 2 is a smooth transition structure.

[0162] The inlet side of the blade 2 is the blade 2 thickness side where the inlet line 212 is located, and the outer edge side is the blade 2 thickness side where the outer edge line 211 is located. The impeller of the embodiment is rounded at the intersection of the two sides.

[0163] Based on the same inventive concept, the application also provides a ventricular assist device corresponding to the impeller of any of the above embodiments.

[0164] The ventricular assist device comprises a catheter and an impeller as in any of the above embodiments arranged in the catheter.

[0165] The working principle of the ventricular assist device is that the catheter of the ventricular assist device is sent to the left ventricle through the femoral artery, the flow inlet of the catheter is located in the left ventricular outflow tract, and the flow outlet of the catheter is located in the aorta. When the ventricular assist device works, the rotating impeller can suck blood from the catheter flow inlet of the left ventricle into the catheter, and then output the blood to the aorta through the catheter flow outlet of the aorta, thereby achieving the effect of heart assistance.

[0166] The ventricular assist device of the above embodiments relies on the corresponding impeller of any of the above embodiments to pump blood, and has the beneficial effects of the corresponding impeller embodiments, which will not be repeated here.

[0167] It should be noted that the above describes some embodiments of the application. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims can be performed in an order different than that described above and still achieve desirable results. In addition, the processes depicted in the figures do not necessarily require the particular order shown or sequential order to achieve desirable results. In some embodiments, multitasking and parallel processing can be advantageous or possible.

[0168] Each embodiment in the application is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be mutually referred to.

[0169] The description of the application is given for the purpose of illustration and description, and is not exhaustive or limiting to the forms disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are chosen and described in order to better illustrate the principles and practical application of the application, and to enable those of ordinary skill in the art to understand the application in order to design various embodiments with various modifications for specific purposes.

[0170] It should be understood by those of ordinary skill in the art that the above discussion of any of the embodiments is merely exemplary in nature and not intended to imply limitations on the scope of the application, including the claims herein; nor has the applicant made any effort to exhaustively describe all possible implementations and permutations of the various embodiments or technical features among the different embodiments; nor are the steps necessarily to be implemented in the order presented; nor are there necessarily many other variations of the different aspects of the embodiments described above that will be apparent to one of ordinary skill in the art upon review of the present description.

[0171] Although the present application has been described in connection with certain specific embodiments thereof, many modifications, changes, alterations, and variations will become apparent to those of ordinary skill in the art once armed with the above description.

[0172] It is intended that the present application embrace all such alternatives, modifications, and variations as falling within the broad scope of the appended claims. Accordingly, any and all such modifications, variations or equivalent arrangements that fall within the scope of this application should be intended to be embraced therein.

Claims

1. An impeller comprising a hub and at least one blade fixed to an outer periphery of the hub, the hub comprising an inlet end and an outlet end, characterised in that, The blade comprises an action surface, and a profile line of the action surface comprises an outer edge line away from the hub, an end point of the outer edge line close to the inlet end is a line start point, and an end point of the outer edge line close to the outlet end is a line end point; The outer edge line is a smooth space curve, and an axial curvature of the outer edge line gradually decreases from the line start point to the line end point, and a rate of change of the axial curvature of the outer edge line also gradually decreases; The outer edge line is a spiral curve with gradually changing curvature, and a formula is as follows: Wherein, x, y and z are space coordinates in a three-dimensional rectangular coordinate system; An included angle between a tangent line of the line start point and a tangential velocity is an inlet included angle of the outer edge line, a resultant velocity of an axial velocity and the tangential velocity of the line start point is a relative velocity, and an included angle between the relative velocity and the tangential velocity of the line start point is an inlet installation angle of the outer edge line, and the inlet included angle is greater than the inlet installation angle.

2. The impeller of claim 1, wherein An angle difference between the inlet included angle and the inlet installation angle is not greater than 5°.

3. The impeller according to claim 1, wherein The inlet installation angle is calculated by a formula as follows: ； wherein a m is the entrance angle, V a is the axial velocity of the line start point, V t is the tangential velocity of the line start point; The axial velocity of the line start point is calculated by a formula as follows: Wherein, Q is a preset flow, A is a sectional area of a pipe hole of a conduit for installing the impeller, and D is an inner diameter of the conduit; The tangential velocity of the line start point is calculated by a formula as follows: In the formula, is the preset rotational speed of the blade.

4. The impeller of claim 1, wherein The inlet included angle is 25° to 35°.

5. The impeller of claim 1, wherein An included angle between an axial plane where the line start point is located and an axial plane where the line end point is located is a blade deflection angle, and the blade deflection angle is 90° to 150°.

6. The impeller of claim 1, wherein The profile line of the action surface further comprises an inlet edge line intersecting with the line start point; and when the impeller is projected in an axial direction of the hub, an included angle between the inlet edge line and the axial direction of the line start point is a tangential forward sweep angle, and the tangential forward sweep angle is 2° to 8°.

7. The impeller of claim 1, wherein The profile line of the action surface further comprises an inlet edge line intersecting with the line start point; and when the impeller is projected in a radial direction of the hub, an included angle between the inlet edge line and a horizontal line is an axial forward sweep angle, and the axial forward sweep angle is 10° to 26°.

8. The impeller of claim 1, wherein In the same radial section of the impeller, a ratio of an outer diameter of the blade to an outer diameter of the hub is 1.25 to 3.

25.

9. The impeller of claim 1, wherein In the axial direction of the hub, a ratio of a length of the blade to a length of the hub is 0.86 to 0.87, and the line end point is close to the outlet end.

10. A ventricular assist device, characterized by The impeller comprises: A conduit and the impeller according to any one of claims 1 to 9 arranged in the conduit.

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