30 results about "Pulsatile flow" patented technology

The invention relates to the technical field of medical instrument volume detection, and discloses a medical instrument internal volume detection system. A continuous wave and a pulse modulation signal are simultaneously transmitted through an annular phased array microwave antenna array, three-dimensional dielectric constant distribution is reconstructed by adopting a compressed sensing algorithm, and Doppler time-frequency domain characteristics are extracted through short-time Fourier transform; and inputting the phase gradient field and Doppler velocity field features into a convolutional neural network to generate a four-dimensional space-time volume evolution model, separating a macroscopic volume trend and a microcosmic pulsation component by adopting an adaptive Kalman filtering algorithm, and predicting an abnormal hemodynamic event through a long-short-term memory network. The technical problem of real-time precise detection of the multi-dimensional volume parameters of the blood circulation medical instrument under the complex pulsating flow condition is solved, and accurate evaluation of the instantaneous volume value, the pulsation amount and the pulsating frequency spectrum and early warning of abnormal events are achieved.

This invention relates to a ball-operated plugging device for downhole pulsating hydraulic fracturing, comprising a main body assembly. A conical valve seat is disposed in the middle of the main body assembly, and an umbrella-shaped valve is slidably connected within the conical valve seat. The umbrella-shaped valve includes a valve head boss and a valve stem. A self-excited oscillation chamber is also provided at the bottom of the conical valve seat. A spring support seat is disposed below the self-excited oscillation chamber, with a central circular hole at the geometric center of the spring support seat. A spring is placed on the spring support seat, and the top of the spring contacts the valve head boss of the umbrella-shaped valve. A through-hole flow channel is provided in the middle of the umbrella-shaped valve, with its upper and lower ends communicating with cavity A and cavity B, respectively. The valve stem of the umbrella-shaped valve passes through the spring, and its bottom is inserted into the central circular hole of the spring support seat. A spherical groove is provided at the top of the umbrella-shaped valve for placing a soluble plugging ball. This invention can adjust the pressure variation of the pulsating fluid at the bottom of the well during construction.

The invention relates to a valve pulsating flow test system which comprises a circulation test loop, a heart simulation system and a pulsating pump, the circulation test loop comprises a first simulation system, a test channel, a second simulation system and a water return channel which are connected in sequence, and gate valves are arranged at the two ends of the test channel; the test channel can be detachably installed between the first simulation system and the second simulation system in a forward or reverse mode, the test channel comprises a flowmeter assembly detachably installed at the water inlet end of the test channel, and the first simulation system comprises a first simulation cavity. The one-way valve can be detachably mounted on the first simulation cavity in a forward or reverse manner; the heart simulation system is connected with the first simulation system; the pulsating pump is connected with the heart simulation system. According to the invention, rapid switching of the installation directions of the one-way valve and the flowmeter can be realized, the test requirements of different types of test samples can be met, and the test efficiency is further improved.

An apparatus for generating a controlled pressure pulsatile flow includes: a fluid flow path extending from a reservoir to an application; a primary pump disposed in the fluid flow path downstream of the reservoir; a reference pump; a variable speed electric motor coupled to the reference pump; a bleed orifice connected in fluid communication with the reference pump; a pressure relay device configured to communicate a reference pressure from the reference pump to the fluid flow path; and an electronic controller configured to selectively supply electric power to the electric motor so as to generate a pulsatile fluid flow in the fluid flow path.

A dampening device includes a housing including an inlet and an outlet, and a section of compliant tubing extending through the housing between the inlet and the outlet. A first portion of the housing is movable relative to a second portion of the housing to vary fluid flow characteristics within the section of compliant tubing. A dampening device includes a housing defining an interior volume, wherein the housing includes an inlet and an outlet, and an actuation mechanism configured to change the interior volume thereby changing fluid flow characteristics through the housing. A method of smoothing a pulsatile fluid flow includes coupling the dampening device to an inflow line, activating the fluid pump, wherein the section of compliant tubing expands within the housing to smooth out the pulsatile fluid flow, and selectively moving a first portion of the housing relative to a second portion to vary fluid flow characteristics.

A vascular simulator based on pulsatile flow control and a method for controlling same are disclosed. The control method according to the present disclosure may comprise the steps of: acquiring pressure sensing information of an artificial blood vessel outlet region due to the flow of artificial blood through a pressure sensor corresponding to the artificial blood vessel outlet region; identifying an outlet pressure corresponding to the artificial blood vessel outlet region on the basis of the pressure sensing information; if the outlet pressure is identified, identifying whether the outlet pressure matches a preset condition; and if the outlet pressure does not match the preset condition, controlling a valve corresponding to the outlet such that the outlet pressure matches the preset condition.

A system for simulating cardiovascular fluid flow having a target fluid flow profile, which has target pulsatile flow and target systemic resistance components, in a test member is disclosed. The system includes a reservoir, a pump, input and output channels, a first valve in the input channel, a second valve in the output channel, and a processor. The input and output channels are connectable to the test member so as to form a fluid circuit with the test member. The processor is configured to execute a method for controlling the first valve to generate the target pulsatile flow component in the input channel, and controlling the second valve to generate the target systemic pressure component. Other systems are also disclosed. Methods for simulating target fluid flow profiles in a test member are also disclosed.

This invention provides a pulsating flow generator that can efficiently pulsate the pressure of a liquid, has a simple configuration, and is highly durable. [Solution] The problem of the present invention is solved in a pulsating flow generator 1 provided in a flow path between a liquid supply means and a nozzle that sprays liquid, which causes the flow rate of the liquid sprayed from the nozzle to change in accordance with the pressure pulsation by causing the pressure of the liquid flowing through the flow path to pulsate. The pulsating flow generator 1 comprises a main body 2 having a main flow path through which liquid flows from the liquid supply means toward the nozzle, and a pulsation generating unit 4 having a volume fluctuation unit that alternately absorbs and releases the liquid flowing through the main flow path via a branch path to which the flow path branches off, thereby increasing and decreasing the internal volume. The pulsation generating unit 4 solves the problem by alternately repeating a filling step of absorbing liquid from the main flow path and a release step of releasing the absorbed liquid into the main flow path when liquid is supplied at the input liquid pressure, thereby superimposing the fluctuating volume fluctuation pressure on the input liquid pressure of the liquid and causing the liquid pressure to pulsate.

The invention discloses a pulsating flow blood injury assessment system and method for a double-loop nested low-pre-charge medical instrument, and belongs to the technical field of medical instruments. The system comprises a physiological pulsating pressure simulation loop and an instrument test blood carrying loop. The physiological pulsating pressure simulation loop is composed of a mechanical human body circulation simulation system and comprises a left ventricle, an aorta compliance cavity, a pipeline, a sensor and a power system. The instrument test blood carrying loop comprises a flexible blood bag, a blood carrying pipeline and a to-be-tested medical instrument. The two loops are nested and coupled through the flexible blood bag, and the flexible blood bag is immersed in water-glycerol liquid of the physiological pulsating pressure simulation loop to realize non-contact pressure transmission. The total blood pre-filling amount of the system is smaller than 500 mL, an SEBS blood bag and a heparinization coating are adopted, a non-contact sensor and an actuator are combined, and extra blood damage is remarkably reduced. According to the invention, low-pre-charge and high-biocompatibility pulsating flow blood injury accurate evaluation is realized, and the method is suitable for blood compatibility test of medical instruments such as a ventricular assist device and the like.

The invention discloses a left heart circulation pulsating flow test system and test method. The test system comprises a controller, a rack and a circulation loop, the circulation loop is arranged on the rack, a vein system in the circulation loop is connected with an inlet of a left atrial cavity, an outlet of the left atrial cavity is connected with a left ventricular model, and the left ventricular model is arranged in the left ventricular cavity; an outlet of the left ventricle model is connected with the aorta model which simulates a real human physiological structure; an outlet of the aorta model is connected with the artery compliance cavity, and an outlet of the artery compliance cavity is connected with the vein system. A servo electric cylinder is adopted in the power executing mechanism, a piston is pushed through the servo electric cylinder, piston displacement, system flow and pressure of all cavities are monitored, and the real left ventricle movement rule of the human body physiology is simulated. The device is stable in operation, reliable in performance and high in precision.

This invention provides a systemic-pulmonary dual-circulation simulation system for testing the hemodynamic performance of an artificial heart. It includes a cardiovascular silicone model, a ventricular pulsation device, a controller, a data acquisition device, a fluid reservoir, and an artificial heart. The cardiovascular silicone model, ventricular pulsation device, and fluid reservoir are connected in series to form a blood circulation loop. The cardiovascular silicone model includes systemic and pulmonary circulation loops; the ventricular pulsation device has an internal electric cylinder that drives a piston to reciprocate via a push rod, causing fluid flow in the blood circulation loop; the controller controls the movement of the ventricular pulsation device to simulate blood flow with physiological pulsatile flow characteristics; the data acquisition device collects pressure and flow rate data at different locations on the cardiovascular silicone model. This invention can not only completely simulate the blood flow patterns of the human cardiovascular system but also be used to test the impact of artificial heart implantation on the hemodynamic performance of the human cardiovascular system under different physiological conditions, contributing to the development and research of artificial hearts.

This invention provides a vertical heat exchanger with dual inlet headers. The lower header at the inlet is divided into a left header and a right header by a partition. The left heat exchange tube is connected to the left header, and the right heat exchange tube is connected to the right header. The left and right headers are respectively equipped with left and right inlets, and the fluid flow rates at the left and right inlets can be controlled independently. The fluid entering the left and right headers is a pulsating flow with constantly changing velocity. This invention uses the pulsating flow to continuously impact the fluid within the baffle cavity, thereby causing continuous fluid agitation and further enhancing heat transfer.

The present application relates to the technical field of venturi flow calculation, and particularly relates to a venturi pulsating flow correction method, device, equipment and storage medium. The method comprises the following steps: determining a venturi initial flow based on a steady-state flow measurement equation according to an original monitoring pressure difference between a venturi inlet section and a throat, a venturi inlet pressure and a venturi inlet temperature; determining a transient part interference pressure difference in the fluid based on a venturi pulsating flow pressure difference equation according to the venturi initial flow; obtaining a corrected pressure difference according to the original monitoring pressure difference and the transient part interference pressure difference; and obtaining a corrected flow based on the steady-state flow measurement equation according to the corrected pressure difference. The method can solve the problems that the mathematical model only considering the steady-state flow in the prior art may cause certain deviation in the calculation of the flow or even distortion of the measurement result, and the algorithm convergence is difficult when the pulsating flow is considered.

A centrifugal nozzle, an apparatus, and a method for measuring the pulsating flow rate of a liquid are provided. The centrifugal nozzle includes: a centrifugal nozzle housing with a swirling channel for liquid flow; a first measuring electrode and a second measuring electrode, symmetrically arranged and fixed to the inner wall of the swirling channel, wherein the inner surface arc diameter of the first and second measuring electrodes is equal to the diameter of the swirling channel; wherein the first and second measuring electrodes constitute a capacitive sensor, and the thickness of the annular adherent liquid film formed when the liquid flow enters the swirling channel is indirectly obtained by measuring the capacitance signal of the annular adherent liquid film. This application first measures the liquid film thickness based on the capacitance method, and then determines the pulsating flow rate of the liquid flow through the mapping relationship between the liquid film thickness and the pulsating flow rate, thereby achieving accurate measurement of the pulsating flow rate of non-conductive cryogenic liquids.

The orifice plate flowmeter throttling device comprises a flowmeter assembly, a flowmeter orifice plate is arranged at the lower end of the flowmeter assembly, and the left side of the flowmeter orifice plate is sequentially connected with a pulsation restraining mechanism and a buffering mechanism. The pulsation suppression mechanism comprises a corrugated buffer tube, the left end of the corrugated buffer tube is connected with the buffer mechanism through a first flange, and the right end is connected with the flowmeter orifice plate through a second flange; the buffering mechanism comprises a first buffering pipe cavity and a second buffering pipe cavity, a rotating seat is arranged in the first buffering pipe cavity, a bullet head is fixed to the left end of the rotating seat, a spiral flow guide piece is installed on the surface of the rotating seat, the first buffering pipe cavity is coaxially connected with the second buffering pipe cavity, and a honeycomb flow guide plate is arranged in the second buffering pipe cavity. According to the orifice plate flowmeter throttling device, through the dual effects of flow field reconstruction of the buffer mechanism and dynamic damping of the pulsation suppression mechanism, the measurement repeatability error of an orifice plate flowmeter under the pulsating flow working condition is greatly reduced, and the pressure deviation rate is effectively controlled.

The invention relates to a self-adaptive control artificial heart valve testing device. The testing device comprises a pulsation generation module used for generating pulsation fluid simulating systole and diastole of the heart; the sensing feedback system is used for carrying out data acquisition on the pulsating fluid and feeding back the acquired fluid data to the control system; the control system is used for adaptively adjusting working state parameters of the pulsation generation module, the liquid volume execution unit and the liquid resistance execution unit according to the fluid data so as to realize pulsating flow in a near physiological state; and the valve loading module is used for installing a to-be-tested heart valve prosthesis, so that the heart valve prosthesis can be tested by utilizing pulsating fluid in a near-physiological state, and a testing device which can realize stable and continuous pulsating flow close to a real physiological state in vitro and has self-adaptive regulation and control capability is realized. The method is of great significance to simulation of pathological states of different patients, improvement of data consistency among laboratories and acceleration of research, development and manufacturing of artificial heart valves.

Ablation electrode assemblies include an inner core member and an outer shell surrounding the inner core member. The inner core member and the outer shell define a space or separation region therebetween. The inner core member is constructed from a thermally insulative material having a reduced thermal conductivity. In an embodiment, the space is a sealed or evacuated region. In other embodiments, irrigation fluid flows within the space. The ablation electrode assembly further includes at least one thermal sensor in some embodiments. Methods for providing irrigation fluid during cardiac ablation of targeted tissue are disclosed that include calculating the energy delivered to irrigation fluid as it flows within the ablation electrode assembly through temperature measurement of the irrigation fluid. Pulsatile flow of irrigation fluid can be utilized in some embodiments of the disclosure.

A device for the temporary circulatory assistance or back-up of the heart of a patient including: a linear actuator configured to move a membrane in a chamber so as to cause a pulsating fluid flow adapted to support the activity of the heart of the patient, which flow is characterised by a succession of phases of aspiration and phases of ejection of the fluid, a control unit configured to pilot the actuator and control the movement of the membrane, which piloting is carried out while taking into account input data originating from an ECG signal of the patient, the control unit is configured to determine a time offset between the instant at which the QRS complex of the ECG signal is detected and the instant at which an ejection phase is initiated.

A right ventricular assist device (RVAD) (420) is provided that includes a pulsatile- flow pump (424) defining a pump chamber (426) that includes first and second sub- chambers (427A, 427B) in fluid isolation from each other. Proximal and distal cannulas (438, 432) are configured to be inserted into a right ventricle (450) and couplable to an artery (302) of the systemic circulation, respectively, and arranged in fluid communication with a proximal opening (428) of the first sub-chamber (427A) and a distal opening (430) of the second sub-chamber (427B), respectively. The pulsatile-flow pump (424) provides pulsatile flow synchronized with the cardiac cycle in a counterpulsation mode by, during at least a portion of ventricular diastole, pumping blood in a distal direction out of the distal opening (430) and drawing blood in the distal direction into the proximal opening (428); and during at least a portion of ventricular systole, pumping blood in the opposite direction. Other embodiments are also described.

A system for simulating cardiovascular fluid flow having a target fluid flow profile, which has target pulsatile flow and target systemic resistance components, in a test member is disclosed. The system includes a reservoir, a pump, input and output channels, a first valve in the input channel, a second valve in the output channel, and a processor. The input and output channels are connectable to the test member so as to form a fluid circuit with the test member. The processor is configured to execute a method for controlling the first valve to generate the target pulsatile flow component in the input channel, and controlling the second valve to generate the target systemic pressure component. Other systems are also disclosed. Methods for simulating target fluid flow profiles in a test member are also disclosed.

A pulsatile flow device configured to be implanted in a ventricle of a heart, has: an enclosure having an internal volume, the enclosure having a wall side for facing a myocardium of the heart and a ventricle side for being exposed to blood flowing in the ventricle, the ventricle side defined at least partially by a membrane, the membrane movable between a diastolic position and a systolic position, the internal volume greater in the systolic position than in the diastolic position; a frame located within the enclosure, the frame engaging the wall side of the enclosure, the frame exerting a force on the wall side to resist deformation of the wall side of the enclosure; and an actuator operatively connected to the enclosure, the actuator operable to move the membrane between the diastolic position and the systolic position.

This invention provides a method, apparatus, and electronic device for improving the fluidity of porous media using pulsating flow. The method includes: determining a critical threshold and a subcritical baseline; applying a steady-state displacement with a displacement intensity equal to the subcritical baseline, and superimposing a pulsating drive; using a solution framework to advance the interfacial motion of droplets under pulsating drive over time, adaptively controlling the time step during the advancement process, the time step being jointly limited by multiple physical constraints; determining the truncated axial net displacement of the droplet within the pore throat contraction structure within a fixed observation time window; obtaining the fluidity index corresponding to the pulsating drive based on the truncated axial net displacement; keeping the amplitude of the pulsating drive constant, changing the frequency of the pulsating drive to obtain a first curve of the fluidity index changing with frequency, and determining a cutoff frequency based on the first curve; changing the amplitude of the pulsating drive to obtain a second curve of the cutoff frequency changing with amplitude. This method is suitable for engineering parameter design and selection and is reproducible.

The application discloses a kind of hydraulic pipe pressure washing integrated control system and device, it is related to hydraulic pipeline detection technical field;The system includes power liquid supply module, fluid-structure coupling sensing module, circulation test loop module and main control processing module, main control processing module controls output pulsatile fluid to be tested hydraulic pipe and carries out cleaning, using cross-correlation operation processing collected flow and pressure sequence to extract phase lag, and then solve pipeline relaxation time constant;By monitoring transient flow resistance value and its change gradient to automatically determine that cleaning is completed;In the pressure maintaining test stage, system blocks oil return passage, according to relaxation time constant to construct pressure natural attenuation reference curve reflecting material creep characteristic, and by calculating the residual of real-time pressure and reference curve to distinguish material deformation and fluid leakage.The application not only realizes the self-adaptive control of cleaning process, but also eliminates the false judgment influence of pipeline viscoelasticity on sealing detection.

This invention proposes an in vitro testing device for the aortic valve and ascending aorta, comprising a chamber system, a drive system, a circuit system, a chamber auxiliary system, a control system, and a particle image velocimetry system. Based on patient medical images, this device constructs a 1:1 personalized aortic valve and ascending aorta vascular model, realistically simulating an individualized hemodynamic environment through closed-loop pulsatile flow circulation. It can rapidly and quantitatively acquire complex functional parameters such as blood flow velocity, pressure, wall shear force, and relative particle residence time, overcoming the limitations of traditional imaging providing only morphological data and CFD simulation relying on ideal assumptions. Simultaneously, it can be used for individualized in vitro testing of artificial aortic valves, evaluating their performance in specific anatomical structures, significantly improving the accuracy of preoperative planning, postoperative prediction, and device development. This device has advantages such as high physiological fidelity, high testing efficiency, and strong result repeatability, making it suitable for precision cardiovascular diagnosis and treatment and evaluation of implantable interventional devices.

The invention relates to a device for temporary circulatory support or replacement of the heart (13) of a patient (12), comprising: a linear actuator (10) configured to move a membrane (70) within a chamber (11) so as to induce a pulsatile fluid flow capable of supporting the activity of the patient's heart, which flow is characterized by a succession of aspiration and ejection phases of the fluid; a control unit (40) configured to drive the actuator (10) and control the movement of the membrane (70), which control is achieved by taking into account input data from an ECG signal of the patient (12); the control unit (40) is configured to determine a time lag ∆T between the time TR when the QRS complex of the ECG signal is detected and the time when an ejection phase is initiated. Figure to be published with the abbreviation: Fig. 1

A pulsating flow generation device is provided with: a fluid element (30) having a common flow path (34) into which a working fluid flows from the upstream side, and a first branch flow path (36) and a second branch flow path (38) which are connected to the common flow path (34); and a pressure accumulator (32) to which the working fluid is supplied from the common flow path (34) via the first branch flow path (36), a second branch flow path (38) for supplying the working fluid supplied from the common flow path to a discharge section (20) for discharging the working fluid, and a fluid element (30) for discharging the working fluid from the common flow path (34) when the working fluid flows into the common flow path (34). A first flow state in which the flow rate of the working fluid supplied from the common flow path (34) to the first branch flow path (36) increases and a second flow state in which the flow rate of the working fluid supplied from the common flow path (34) to the second branch flow path (38) increases can be automatically and continuously switched.

The invention provides a pressure pulsation auxiliary control method and system for cardiovascular simulation circulation and electronic equipment, and relates to the technical field of medical simulation and auxiliary control, and the method comprises the steps: obtaining a target cardiovascular pressure waveform signal; performing Fourier transform on the target cardiovascular pressure waveform signal to obtain amplitudes of first n harmonic components; generating a first pulse width modulation signal for controlling a first pump body based on the amplitudes of the first n harmonic components so as to drive the first pump body to provide a constant baseline flow; the amplitude values of the first n harmonic components are superposed, and a second pulse width modulation signal used for controlling a second pump body is generated based on the superposed amplitude values so as to drive the second pump body to provide pulsating flow; the baseline flow provided by the first pump body and the pulsating flow provided by the second pump body are converged in a fluid loop to synthesize and output a reconstructed pressure waveform. According to the method, flexible and accurate reproduction of the high-fidelity physiological pressure waveform containing key features such as the rising branch in the systolic period and the dicrotic incisura is realized.

The utility model provides a bionic full-soft pulsating pump based on air driving, and belongs to the technical field of soft robots. The pulsating pump comprises a pump body, a pulsating piece, a pressure relief piece and a valve assembly. The pump body has a pulsating chamber, a first port and a second port. The pulsation piece divides the pulsation cavity into a control cavity and a pumping cavity, and the pulsation piece is configured to deform according to the pressure difference between the control cavity and the pumping cavity. The pressure relief piece is arranged at the second connector and can open or close the second connector according to the pressure in the control cavity. The first end of a first one-way valve of the valve assembly communicates with the pumping cavity, and the second end of a second one-way valve communicates with the pumping cavity. According to the pulsating pump, high-efficiency pumping of pulsating flow is utilized to boost full softening of the pump, development of a full-soft heart is promoted, biological compatibility of the pump and flexibility of the pumping process are improved by changing flexible materials, and a driving scheme can be provided for development of a full-soft driving structure of a follow-up soft robot.

The invention provides a piston type oxygenator capable of producing pulsating blood flow, which comprises a shell, a mandrel, an oxygenation temperature-variable membrane group, a piston and two blocking pieces, the two blocking pieces divide the inner cavity of the shell into a membrane cavity and cavity groups positioned on two sides of the membrane cavity, the shell is provided with a blood inlet, a blood outlet and an inlet and outlet group communicated with the cavity groups, the mandrel and the oxygenation temperature-variable membrane group are arranged in the membrane cavity, and the piston is arranged in the membrane cavity. The core shaft is sleeved with the oxygenation variable-temperature membrane set, the oxygenation variable-temperature membrane set is communicated with the two cavity sets, the blood inlet is communicated with the pulsation cavity of the core shaft, a one-way valve is arranged at the blood inlet, the piston is arranged in the pulsation cavity, a through opening communicated with the pulsation cavity and the membrane cavity is formed in the core shaft, the through opening is located between the blood inlet and the piston, and the blood outlet is communicated with the membrane cavity. According to the device, the blood flow in the oxygenator can be changed from the advection state to the pulsation state, the device better fits the physiological circulation state of the blood of a human body, damage to blood vessels, lungs and kidneys can be reduced, and postoperative recovery of a patient is facilitated; and the blood can stay in the oxygenator for a short time, so that the exchange efficiency of oxygen can be improved.

The application discloses a centrifugal blood pump with constant rotating speed and output pulsating flow, which is characterized by the following technical scheme: a steering gear assembly is arranged in the pump body, an impeller is arranged in the inner cavity of the pump shell, a bevel gear I is arranged at the root of the blade uniformly arranged on the circumference of the impeller, and a driving motor II is used for driving the impeller to rotate; a driving motor I is used for driving the steering gear assembly to work, the steering gear assembly comprises a box body, two output inner gear rings with opposite rotating directions which can rotate axially in the box body, and an input inner gear ring; a steering gear is arranged in the middle of the box body, the steering gear is sleeved on the rotating main shaft of the impeller, one end of the steering gear is engaged with the bevel gear I through the bevel gear II in the impeller, and the straight gear at the other end is connected with an alternate steering mechanism so that the deflection angle of the blade is changed alternately, the rotating range of the blade angle is adjusted by the independent motor driving the related gear mechanism, the blade can be effectively and reliably driven to perform high-frequency angle adjustment, and the blood flow output by the blood pump can meet the pulsating demand of human body under the condition that the rotating speed is constant.