Jinyu Ren, Dezhi Xu, Jing Xu^*

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.3, pp. 561-572, 2020, DOI:10.32604/fdmp.2020.09791

Abstract Submarine maneuverability has been analyzed by means of computational fluid dynamics (CFD). This approach provides an alternative, accurate, and cost-effective method for simulating actual flow. The numerical results show that the numerical simulation of the viscous flow related to a moving submarine based on the RANS equation with a relevant turbulence model can not only provide rich flow field details such as flow separation, but also accurately predict its hydrodynamic performance. The present study indicates that CFD can be used to forecast the submarine’s maneuverability in the initial design stage. The present results will be used in the future as… More >

Guolin Li^*

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.3, pp. 549-559, 2020, DOI:10.32604/fdmp.2020.09219

Abstract The rational design of heating ventilation and air conditioning systems is an important means to achieve energy conservation and sustainable development. The simulation of air-conditioning systems with finite element methods has gradually become an important auxiliary means of complex airspace design. In this paper, a k-ε turbulence model is used to conduct 3D simulations and optimize the summer air conditioning system of a lecture hall. Various conditions are considered in terms of fresh air temperature and flow rate towards the end to improve comfort. The approach used in this paper could also be used in the future as an auxiliary… More >

Chong Liu, Yang Du, Jianjun Liang, Hong Meng, Jian Wang, Peili Zhang^*

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.3, pp. 537-547, 2020, DOI:10.32604/fdmp.2020.09119

Abstract Gas explosion is a process involving complex hydrodynamics and chemical reactions. In order to investigate the interaction between the flame behavior and the dynamic overpressure resulting from the explosion of a premixed gasoline-air mixture in a confined space, a large eddy simulation (LES) strategy coupled with sub-grid combustion model has been implemented. The considered confined space consists of a long duct and four branches symmetrically distributed on both sides of the long duct. Comparisons between the simulated and experimental results have been considered with regard to the flame structure, flame speed and overpressure characteristics. It is shown that the explosion… More >

Tianyu Xu, Lixiang Zhang^*

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.3, pp. 525-536, 2020, DOI:10.32604/fdmp.2020.09618

Abstract In this article, computational fluid dynamics (CFD) are used to explore the dynamics of water transport inside the pitted thickening of a plant xylem vessel. A pitted thickening model combined with the Bernoulli equation is used to analyze the influence of various factors (namely, the inner diameter, thickening width, thickening height, thickening spacing, number of laps and adjacent pit axial rotation). The pressure drop and the flow resistance coefficient are the variable parameters for our analysis. The results show that these two parameters are proportional to the thickening height and thickening width, and inversely proportional to the inner diameter, thickening… More >

Qiping Chen^*, Haoyu Sun, Ning Wang, Zhi Niu, Rui Wan

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.3, pp. 513-524, 2020, DOI:10.32604/fdmp.2020.09375

Abstract The possibility to enhance the stability and robustness of electrohydraulic brake (EHB) systems is considered a subject of great importance in the automotive field. In such a context, the present study focuses on an actuator with a four-way sliding valve and a hydraulic cylinder. A 4-order nonlinear mathematical model is introduced accordingly. Through the linearization of the feedback law of the high order EHB model, a sliding mode control method is proposed for the hydraulic pressure. The hydraulic pressure tracking controls are simulated and analyzed by MATLAB/Simulink soft considering separately different conditions, i.e., a sine wave, a square wave and… More >

Xingkai Zhang, Xuan Zhang, Ruiquan Liao^*

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.3, pp. 501-512, 2020, DOI:10.32604/fdmp.2020.09012

Abstract In order to clarify the influence of the instrument’s own drag on the temperature distribution in the horizontal gas wellbore in temperature logging. By constructing an indoor gas-liquid two-phase horizontal tube flow platform, the effects of the drag speed of the instrument on the temperature distribution in the wellbore were studied in the single-phase gas and gas-liquid two phases. In addition, during the process of instrument dragging, the influence of different perforation cluster opening methods and wellbore inclination on temperature distribution was also studied. The results show that the temperature fluctuation is reduced at higher drag speeds; Under a certain… More >

Daoming Shen^1,2,*, Chao Gui¹, Jinhong Xia¹, Songtao Xue^2,3

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.3, pp. 489-500, 2020, DOI:10.32604/fdmp.2020.08969

Abstract The performances of a refrigeration unit relying on compressors working in parallel have been investigated considering the influence of the compressor volumetric efficiency and isentropic efficiency on the compression ratio. Moreover, the following influential factors have been taken into account: evaporation temperature, condensation temperature and compressor suction-exhaust pressure ratio for different opening conditions of the compressor. The following quantities have been selected as the unit performance measurement indicators: refrigeration capacity, energy efficiency ratio (COP), compressor power consumption, and refrigerant flow rate. The experimental results indicate that the system refrigeration capacity and COP decrease with a decrease in evaporation temperature, increase… More >

Yushan Liu^1,2, Yubin Su³, Zhenhua Wu⁴, Wei Luo^1,2, Ruiquan Liao^1,2,*

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.3, pp. 475-488, 2020, DOI:10.32604/fdmp.2020.08896

Abstract The lifting efficiency and stability of gas lift well are affected by the socalled slippage-loss effect in gas-liquid two-phase flow. The existing studies on this subject have generally been based on vertical and horizontal wells. Only a few of them have considered inclined pipes. In the present work a new focused study is presented along these lines. More specifically, we use the non-slip pressure drop model with Flanigan’s fluctuation correction coefficient formula (together with the parameters of slippage density, slippage pressure drop and slippage ratio) to analyze the influence of the inclination angle on slippage loss for different conditions (different… More >

Chunsheng Wang^*, Dongxing Shang

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.3, pp. 465-473, 2020, DOI:10.32604/fdmp.2020.08828

Abstract Electroosmosis is an effective method for liquid mixing. It is associated with the motion of a liquid in a microchannel induced by an applied electric field. In this manuscript, a numerical model is elaborated and implemented for the case of a straight channel with a single electrode pair. In particular, the Navier-Stokes equation combined with the Convection-diffusion and Helmholtz-Smoluchowski equation are used to simulate the resulting flow field. The influence of various electrode parameters on the mixing efficiency and the related mechanisms are investigated. The numerical results show that a pair of eddies are produced alternately by the changing electric… More >

Latifa M. Al-Balushi, M. M. Rahman^*

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.3, pp. 441-463, 2020, DOI:10.32604/fdmp.2020.08551

Abstract In the present paper, the effect of the heat flux distribution on the natural convective flow inside a square cavity in the presence of a sloping magnetic field and magnetic nanoparticles is explored numerically. The nondimensional governing equations are solved in the framework of a finite element method implemented using the Galerkin approach. The role played by numerous model parameters in influencing the emerging thermal and concentration fields is examined; among them are: the location of the heat source and its lengthH*, the magnitude of the thermal Rayleigh number, the nanoparticles shape and volume fraction, and the Hartmann number. It… More >