Jingying Wang, Fangzhou Han^*, Li Lei, Chunhian Lee

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.3, pp. 601-613, 2020, DOI:10.32604/fdmp.2020.09624 - 25 May 2020

Abstract Accurate aerodynamic heating prediction is of great significance to current manned space flight and deep space exploration missions. The temperature in the shock layer surrounding the reentry vehicle can reach up to 10,000 K and result in remarkable thermochemical nonequilibrium, as well as considerable radiative heat transfer. In general, high-temperature flow simulations coupled with thermal radiation require appropriate numerical schemes and physical models. In this paper, the equations governing hypersonic nonequilibrium flow, based on a three-temperature model combined with a thermal radiation solving approach, are used to investigate the radiation effects in the reentry shock… More >

Lin Wang¹, Chunguo An², Nini Wang², Yaming Ping¹, Kun Wang¹, Ming Gao^1,*, Suoying He¹

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.3, pp. 585-600, 2020, DOI:10.32604/fdmp.2020.09611 - 25 May 2020

Abstract Numerical simulation are conducted to explore the characteristics of the axial inflow and related aerodynamic noise for a large-scale adjustable fan with the installation angle changing from −12° to 12°. In such a range the maximum static (gauge) pressure at the inlet changes from −2280 Pa to 382 Pa, and the minimum static pressure decreases from −3389 Pa to −8000 Pa. As for the axial intermediate flow surface, one low pressure zone is located at the junction of the suction surface and the hub, another is located at the suction surface close to the casing… More >

Ke Sun, Da Li, Hao Liu, Shuzhan Bai^*

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.3, pp. 573-584, 2020, DOI:10.32604/fdmp.2020.09591 - 25 May 2020

Abstract In order to effectively implement DPF (Diesel Particulate Filters) regeneration control, thermal management of exhaust products before and inside Diesel Oxidation Catalyst (DOC) is necessary. In the present study, the Influence of the intake throttle valve and late post injection process on temperature rise inside DOC is analyzed through engine bench tests. The steady experiment results show that adjustment of the intake throttle valve can effectively increase exhaust temperature before DOC; in particular, with intake throttle valve opening at 20%, temperature before DOC can be increased by about 170°C with respect to the full opening.… More >

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 - 25 May 2020

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 More >

Guolin Li^*

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.3, pp. 549-559, 2020, DOI:10.32604/fdmp.2020.09219 - 25 May 2020

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 More >

Tianyu Xu, Lixiang Zhang^*

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.3, pp. 525-536, 2020, DOI:10.32604/fdmp.2020.09618 - 25 May 2020

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 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 - 25 May 2020

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 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 - 25 May 2020

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 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 - 25 May 2020

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 More >

Chunsheng Wang^*, Dongxing Shang

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.3, pp. 465-473, 2020, DOI:10.32604/fdmp.2020.08828 - 25 May 2020

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 More >