Xiao Sun¹, Jiangbo Tong¹, Yuliang Zhang^2,*, Haibing Cai³, Wen Zhou⁴, Xiaoqi Jia⁵, Litao Ou⁶

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.4, pp. 725-737, 2024, DOI:10.32604/fdmp.2023.045541

Abstract Centrifugal pumps are widely used in the metallurgy, coal, and building sectors. In order to study the hydraulic characteristics of a closed impeller centrifugal pump during its shutdown in the so-called power frequency and frequency conversion modes, experiments were carried to determine the characteristic evolution of parameters such as speed, inlet and outlet pressure, head, flow rate and shaft power. A quasi-steady-state method was also used to further investigate these transient behaviors. The results show that, compared to the power frequency input, the performance parameter curves for the frequency conversion input are less volatile and smoother. The characteristic time is… More >

Huaiyin He¹, Longqing Zou¹, Yanchao Li¹, Yixuan Wang¹, Junxiang Li¹, Huan Wen¹, Bei Chang¹, Lijun Liu^2,*

Energy Engineering, Vol.121, No.1, pp. 111-123, 2024, DOI:10.32604/ee.2023.041010

Abstract Multistage multi-cluster hydraulic fracturing has enabled the economic exploitation of shale reservoirs, but the interpretation of hydraulic fracture parameters is challenging. The pressure signals after pump shutdown are influenced by hydraulic fractures, which can reflect the geometric features of hydraulic fracture. The shutdown pressure can be used to interpret the hydraulic fracture parameters in a real-time and cost-effective manner. In this paper, a mathematical model for shutdown pressure evolution is developed considering the effects of wellbore friction, perforation friction and fluid loss in fractures. An efficient numerical simulation method is established by using the method of characteristics. Based on this… More >