Weiwu Jiang¹, Xiaowei Gao^1,2,*

CMES-Computer Modeling in Engineering & Sciences, Vol.140, No.1, pp. 41-76, 2024, DOI:10.32604/cmes.2024.048313

Abstract The collocation method is a widely used numerical method for science and engineering problems governed by partial differential equations. This paper provides a comprehensive review of collocation methods and their applications, focused on elasticity, heat conduction, electromagnetic field analysis, and fluid dynamics. The merits of the collocation method can be attributed to the need for element mesh, simple implementation, high computational efficiency, and ease in handling irregular domain problems since the collocation method is a type of node-based numerical method. Beginning with the fundamental principles of the collocation method, the discretization process in the continuous domain is elucidated, and how… More >

Xin Li¹, Shaohan Zheng^1,2, Yuliang Zhang^1,*, Minfeng Lv³

Frontiers in Heat and Mass Transfer, Vol.21, pp. 245-264, 2023, DOI:10.32604/fhmt.2023.041778

Abstract This article aims to reveal the transient thermal characteristics of the solid domain in a nozzle flowmeter when measuring fluids of varying temperatures. Based on finite element method, the transient numerical calculation of the thermal characteristics of each component of the nozzle flowmeter has been conducted. The research shows that: as the fluid passes through the flowmeter, the high heat flux area inside the nozzle flowmeter gradually transfer from the center of the nozzle to the inlet and outlet, as well as the pressure tapping points upstream and downstream; High thermal stress zones are present near the upstream and downstream… More >

Xiao Sun^a, Fan-Kang Zeng^a, Jia-Bing Yang^a, Feng-Lin Zhou^a, Yu-Liang Zhang^b,*

Frontiers in Heat and Mass Transfer, Vol.17, pp. 1-6, 2021, DOI:10.5098/hmt.17.5

Abstract In order to better study the internal flow characteristics of centrifugal pump as turbine, CFX software is employed to carry out numerical simulation to obtain flow field under different working conditions for pump as turbine based on the standard k - epsilon turbulence model and the SIMPLEC algorithm. The efficiency curves of the pump and pump as turbine are obtained under different working conditions. The results show that the effciency characteristics of the pump change greatly during the process of pumping. The efficiency of the turbine is higher than that of the pump under the respective optimal operating conditions. The… More >

L. Cheng, Y. L. Zhang^†

Frontiers in Heat and Mass Transfer, Vol.18, pp. 1-6, 2022, DOI:10.5098/hmt.18.26

Abstract To obtain the transient characteristics of a centrifugal pump during a rapid startup process accurately, a circulating piping system, including the pump, is established. A full three-dimensional unsteady incompressible viscous flow of a low-specific speed centrifugal pump during rapid startup is numerically simulated using the finite volume method, RNG k-ε turbulence model, sliding grid technology, dynamic grid technology, and userdefined function. Results show that the effect of dynamic and static interference becomes remarkably evident with the increase in speed in the starting process. The effect of dynamic and static interference makes the flow rate show small fluctuation characteristics, and the… More >

Feng-Lin Zhou^a , Kai-Yuan Zhang ^a, Liang Cheng^b,† , Hai-Bing Cai^c, Yu-Liang Zhang^b, Min-Feng Lv^d

Frontiers in Heat and Mass Transfer, Vol.20, pp. 1-10, 2023, DOI:10.5098/hmt.20.22

Abstract In order to grasp the reverse startup characteristics of a small radial vane pump in the case of misoperation, a circulation piping system that includes the pump is established. Numerical simulation of the full three-dimensional unsteady incompressible viscous flow is performed based on the slip-grid technique and user-defined functions (UDF). According to the results, the static pressure fluctuation is small at the inlet of the centrifugal pump during the reverse startup, which differs significantly from the forward startup. Compared to the impeller rotational speed, the time required for the shaft power, head and flow curves to reach stability is lagged,… More >

L.H. Tong^a , Y.L. Zhang^b,†, T.H. Yu^a, B.Y. Luo^c, J.F. Li^b

Frontiers in Heat and Mass Transfer, Vol.20, pp. 1-8, 2023, DOI:10.5098/hmt.20.10

Abstract In order to explore the thermal characteristics of a small nozzle flowmeter in the solid domain when transporting medium with different temperatures, the steady and transient thermal characteristics of each component of the nozzle flowmeter are calculated based on the finite element method. Results showed that the numerical calculation method could effectively reveal the internal thermal characteristics. When transporting high temperature medium, there was an obvious temperature stratification near the inner wall; when the inner wall temperature rose from 50 °C to 700 °C, the heat flow field at the inlet and outlet of the flowmeter increased significantly with the… More >

Deng Qin¹, Tian Li^1,*, Honglin Wang², Jizhong Yang³, Yao Jiang³, Jiye Zhang¹, Haiquan Bi²

CMES-Computer Modeling in Engineering & Sciences, Vol.130, No.3, pp. 1371-1386, 2022, DOI:10.32604/cmes.2022.018480

Abstract The aerodynamic noise of high-speed trains passing through a tunnel has gradually become an important issue. Numerical approaches for predicting the aerodynamic noise sources of high-speed trains running in tunnels are the key to alleviating aerodynamic noise issues. In this paper, two typical numerical methods are used to calculate the aerodynamic noise of high-speed trains. These are the static method combined with non-reflective boundary conditions and the dynamic mesh method combined with adaptive mesh. The fluctuating pressure, flow field and aerodynamic noise source are numerically simulated using the above methods. The results show that the fluctuating pressure, flow field structure… More >

Xiaorui Cheng^1,2,*, Xiang Liu¹, Boru Lv¹

FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.1, pp. 93-107, 2022, DOI:10.32604/fdmp.2022.017566

Abstract An AP1000 nuclear reactor coolant pump is considered to assess the influence of the Impeller/Guide vane clearance on the performances of this type of pumps. Experiments and numerical simulations relying on an unidirectional fluid-solid coupling approach are used to investigate the problem (stress, strain and mode of the rotor). The results reveal the relationship existing between the hydraulic performance of the nuclear reactor coolant pump and the clearance ratio. The effect of clearance ratio on the maximum equivalent stress on the back surface of the impeller blade is greater than that on the working surface (the maximum equivalent stress on… More >

Jianxin Hu, Xin Huang, Yuzhen Jin^*

FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.3, pp. 597-614, 2021, DOI:10.32604/fdmp.2021.014249

Abstract By studying the characteristics of the flow field around a swimming fish, useful insights can be obtained into the superior swimming capabilities developed by nature over millions of years, in comparison to what can be achieved using the standard engineering principles traditionally employed in naval and ocean engineering. In the present study, the flow field related to a single joint fish model is simulated in the framework of a commercial computational fluid dynamics software (ANSYS Fluent 18.0). The principle of the anti-Kármán vortex street is analyzed and the relationship between the direction of the tail vortex and the direction of… More >

Yue Feng¹, Youjun Liu^1,*

Molecular & Cellular Biomechanics, Vol.16, Suppl.1, pp. 31-32, 2019, DOI:10.32604/mcb.2019.05713

Abstract Coronary atherosclerotic heart disease, or coronary heart disease for short, is a heart disease caused by atherosclerotic lesions of coronary arteries, resulting in stenosis, spasm and live obstruction, leading to myocardial ischemia, hypoxia and even necrosis, and is the most common type of organ lesions caused by atherosclerosis. Coronary computed tomograph angiography (CCTA) has been the most effective method for examining coronary heart disease, but this method can only be judged from the morphology. It has been shown that when the coronary stenosis rate is as high as 70%, only 32% of blood vessels can cause myocardial ischemia. Therefore, there… More >