Xiao Sun¹, Huifan Huang¹, Yuliang Zhang², Lianghuai Tong^3,*, Xiaowei Xu², Xiaoqi Jia⁴, Litao Ou⁵

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.10, pp. 2251-2264, 2024, DOI:10.32604/fdmp.2024.050997 - 23 September 2024

Abstract In order to obtain the transient characteristics of a low-speed centrifugal pump during the start-up and shutdown stages, dedicated experimental tests were conducted with eight different valve opening conditions. The Pearson correlation coefficient was used to reveal the linear correlation between variables. According to the results, the stable rotational speed decreases with increasing valve opening (rotational speed decreases from approximately 1472 to 1453 r/min), while the stable shaft power exhibits an increasing trend (shaft power increases from approximately 0.242 to 0.390 kW). The stable time and zeroing time of each parameter during start-up and shutdown More >

Dawei Ruan¹, Mingwei Hu^1,2,3,4,5,*

CMES-Computer Modeling in Engineering & Sciences, Vol.140, No.1, pp. 821-844, 2024, DOI:10.32604/cmes.2024.048392 - 16 April 2024

Abstract The specialized equipment utilized in long-line tunnel engineering is evolving towards large-scale, multifunctional, and complex orientations. The vibration caused by the high-frequency units during regular operation is supported by the foundation of the units, and the magnitude of vibration and the operating frequency fluctuate in different engineering contexts, leading to variations in the dynamic response of the foundation. The high-frequency units yield significantly diverse outcomes under different startup conditions and times, resulting in failure to meet operational requirements, influencing the normal function of the tunnel, and causing harm to the foundation structure, personnel, and property… 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… 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 More >

Nasreen Anjum^1,*, Zhaohui Yang¹, Imran Khan², Mahreen Kiran³, Falin Wu⁴, Khaled Rabie⁵, Shikh Muhammad Bahaei¹

CMC-Computers, Materials & Continua, Vol.67, No.2, pp. 1759-1780, 2021, DOI:10.32604/cmc.2021.014635 - 05 February 2021

Abstract In this paper, we propose a two-tiered segment-based Device-to-Device (S-D2D) caching approach to decrease the startup and playback delay experienced by Video-on-Demand (VoD) users in a cellular network. In the S-D2D caching approach cache space of each mobile device is divided into two cache-blocks. The first cache-block reserve for caching and delivering the beginning portion of the most popular video files and the second cache-block caches the latter portion of the requested video files ‘fully or partially’ depending on the users’ video watching behaviour and popularity of videos. In this approach before caching, video is… More >