Comparison and validation of various turbulence models for U-bend flow with a magnetic resonance velocimetry experiment

Han, Yong; Zhou, Lian; Liu, Bai; Shi, Weidong; Agarwal, Ramesh K.

doi:10.1063/5.0073910

Cited by 37 publications

(9 citation statements)

References 43 publications

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“…In contrast to most physiological controllers, the proposed strategy does not need additional sensors for decision making, lowers the risk of thrombosis, and does not reduce the reliability of a system. Computational simulations showed that it can generate adequate blood flow and pressure and does not possess the disadvantages of insufficient accuracy caused by equipped sensors [ 47 , 48 ]; and (4) the control strategy proposed in this paper is suitable for all kinds of rotary blood pumps, as long as the operating conditions of the blood pump under different requirements are known, and its operating range meets the requirements of variable-speed control.…”

Section: Discussionmentioning

confidence: 99%

Control Strategy Design of a Microblood Pump Based on Heart-Rate Feedback

et al. 2022

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Based on the nonlinear relationship between heart rate and stroke volume, a flow model of left ventricular circulation was improved, and a variable-speed blood-pump control strategy based on heart-rate feedback was proposed. The control strategy was implemented on a system combining the rotary blood pump and blood circulation models of heart failure. The aortic flow of a healthy heart at different heart rates was the desired control goal. Changes in heart rate were monitored and pump speed was adjusted so that the output flow and aortic pressure of the system would match a normal heart in real time to achieve the best auxiliary state. After simulation with MATLAB, the cardiac output satisfied the ideal perfusion requirements at different heart rates, and aortic pressure demonstrated lifting and had good pulsatile performance when a variable-speed blood pump was used. The coupled model reflected the relationship between hemodynamic parameters at different heart rates with the use of the variable-speed blood pump, providing a theoretical basis for the blood-pump-assisted treatment of heart failure and the design of physiological control strategies.

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Section: Discussionmentioning

confidence: 99%

Control Strategy Design of a Microblood Pump Based on Heart-Rate Feedback

et al. 2022

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“…The Wray-Agarwal (W-A) turbulence model is a single-equation turbulence model established by the k-ε closed model [43]. The W-A turbulence model uses the ω equation with cross-diffusion terms, but also retains the link to the k-ε model, which improves the accuracy of predicting equilibrium flow and the ability to interpret non-equilibrium flow [44].…”

Section: Turbulence Model Verificationmentioning

confidence: 99%

A Numerical Study of a Submerged Water Jet Impinging on a Stationary Wall

Wang

Liu³

et al. 2022

JMSE

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The impinging jet is a classical flow model with relatively simple geometric boundary conditions, and it is widely used in marine engineering. In recent years, scholars have conducted more and more fundamental studies on impact jets, but most of the classical turbulence models are used in numerical simulations, and the accuracy of their calculation results is still a problem in regions with large changes in velocity gradients such as the impact zone. In order to study the complex flow characteristics of the water flow under the condition of a submerged jet impacting a stationary wall, the Wray–Agarwal turbulence model was chosen for the Computational Fluid Dynamics (CFD) numerical simulation study of the impacting jet. Continuous jets with different Reynolds numbers and different impact heights H/D were used to impact the stationary wall, and the results show that the jet flow structure depends on the impact height and is relatively independent of the Reynolds number. With the increase in the impact height, the diffusion of the jet reaching the impact area gradually increases, and its velocity gradually decreases. As the impact height increases, the maximum pressure coefficient decreases and the rate of decrease increases gradually, and the dimensionless pressure distribution is almost constant. In this paper, the flow field structure and pressure characteristics of a continuous submerged jet impacting a stationary wall are explored in depth, which is of great guidance to engineering practice.

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“…However, the pulsating velocity component cannot be calculated in the Reynolds average equation. This paper adopts the k-epsilon turbulence (Shi et al, 2020;Han et al, 2021) model. Therefore, the entropy generation rate produced by the pulsating velocity can be approximated by the following formula.…”

Section: Simulation Analysis Entropy Generation Theorymentioning

confidence: 99%

Entropy Analysis of a Valveless Piezoelectric Pump With Hyperbolic Tubes

Yang

2022

Front. Energy Res.

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In order to solve the problems of large reflux and low output performance of the valveless piezoelectric pump with conical tubes, the valveless piezoelectric pump with hyperbolic tubes was proposed. However, the previous research only paid attention to the difference of forward and reverse flow resistance inside the tubes. For this reason, the prototypes of conical tube valveless piezoelectric pump and hyperbolic tubes valveless piezoelectric pump were fabricated in this paper. The maximum output flow rate of the valveless piezoelectric pump with hyperbolic tubes was 54 ml/min. Subsequently, the size and position of entropy production of the hyperbolic tube and the conical tube were numerically calculated based on entropy production theory in this paper. The results show that the entropy production rate of the hyperbolic tube was significantly lower than that of the conical tube, which is consistent with the experimental results. This research analyzed the energy loss inside the valveless piezoelectric pump by using the entropy generation theory, and provided a new design and research method for improving the output performance of the valveless piezoelectric pump in the future.

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Comparison and validation of various turbulence models for U-bend flow with a magnetic resonance velocimetry experiment

Cited by 37 publications

References 43 publications

Control Strategy Design of a Microblood Pump Based on Heart-Rate Feedback

Control Strategy Design of a Microblood Pump Based on Heart-Rate Feedback

A Numerical Study of a Submerged Water Jet Impinging on a Stationary Wall

Entropy Analysis of a Valveless Piezoelectric Pump With Hyperbolic Tubes

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