Zhengqiang Peng^1,*, Rendong Feng¹, Fang Han¹, Jing Guo¹, Shen Chi¹, Wenao Huang¹, Jie Luo²

FDMP-Fluid Dynamics & Materials Processing, Vol.21, No.12, pp. 2945-2961, 2025, DOI:10.32604/fdmp.2025.073281 - 31 December 2025

Abstract Jet pumps often suffer from efficiency losses due to the intense mixing of power and suction fluids, which leads to significant kinetic energy dissipation. Enhancing the efficiency of such pumps requires careful optimization of their structural parameters. In this study, a computational fluid dynamics (CFD) model of a hydraulic jet sand-flushing pump is developed to investigate the effects of throat-to-nozzle distance, area ratio, and throat length on the pump’s sand-carrying performance. An orthogonal experimental design is employed to optimize the structural parameters, while the influence of sand characteristics on pumping performance is systematically evaluated. Complementary… More >

Zhengqing Zhang^1,2,3,*, Xiaojun Yuan², Hui Wu²

FDMP-Fluid Dynamics & Materials Processing, Vol.21, No.12, pp. 2927-2943, 2025, DOI:10.32604/fdmp.2025.071115 - 31 December 2025

Abstract Frost accumulation on the evaporator fins of air source heat pumps (ASHPs) severely degrades heat transfer performance and overall system efficiency. To address this, the present study employs computational fluid dynamics (CFD) to investigate how fin spacing influences frosting behavior, emphasizing the coupled evolution of frost thickness, density, airflow, and temperature distribution within fin channels. Results reveal that fin spacing is a key parameter governing both the extent and rate of frost growth. Wider fin spacing enhances frost accumulation, with a final frost mass of 6.41 g at 12 mm, about 71.8% higher than at More >

Jinyou Qiu^1,2, Jiale Liu^1,2, Yubing Li^1,2,*, Shaogeng Zhong³, Guilong Dai^1,2, Wenhua Liu⁴

Frontiers in Heat and Mass Transfer, Vol.23, No.6, pp. 2025-2049, 2025, DOI:10.32604/fhmt.2025.072260 - 31 December 2025

Abstract The growing demand for energy-saving and renewable heating solutions has made photovoltaic/thermal (PV/T) heat pump systems a promising technology. However, their thermal and electrical performance, as well as the overall utilization of solar energy, strongly depend on capacity configuration and operating parameters. To address this issue, this study proposes a PV/T heat pump system featuring a novel rhombic flow channel structure that functions as the collector-evaporator. An experimental test bench was established to evaluate system performance, and a one-dimensional numerical model was developed to investigate the effects of environmental and operating parameters. The simulation results… More > Graphic Abstract

Ashna Abduljabbar Haji^*, Ranj S. Abdullah^*

Energy Engineering, Vol.122, No.12, pp. 5111-5127, 2025, DOI:10.32604/ee.2025.073367 - 27 November 2025

Abstract The hybrid photovoltaic solar-assisted heat pump are primarily used to generate electricity and provide thermal energy for heating applications. This study investigates the performance enhancement of a hybrid Photovoltaic Thermal Solar-Assisted Heat Pump (PV/T-SAHP) system integrated with a solar tracking mechanism. The system was simulated using TRNSYS to evaluate its monthly electrical output and coefficient of performance (COP) of the heat pump system over a year. The results showed a significant improvement in energy generation and efficiency compared to a conventional PV/T system without SAHP system. Overall, the solar tracking configuration of the PV/T-SAHP generated… More > Graphic Abstract

Shuxin Tan¹, Wei Yan², Lei Zhao¹, Xianglin Zhang^3,*, Ziqiang Man², Yu Lu², Teng Liu², Gaoyue Zhong², Weiqun Liu², Linjun Shi³

Energy Engineering, Vol.122, No.12, pp. 5175-5197, 2025, DOI:10.32604/ee.2025.068692 - 27 November 2025

Abstract The integration of large-scale renewable energy introduces frequency instability challenges due to inherent intermittency. While doubly-fed pumped storage units (DFPSUs) offer frequency regulation potential in pumping mode, conventional strategies fail to address hydraulic-mechanical coupling dynamics and operational constraints, limiting their effectiveness. This paper presents an innovative primary frequency control strategy for double-fed pumped storage units (DFPSUs) operating in pumping mode, integrating an adaptive parameter calculation method. This method is constrained by operational speed and power limits, addressing key performance factors. A dynamic model that incorporates the reversible pump-turbine characteristics is developed to translate frequency deviations… More >

Ali Abdulshaheed^1,*, Faizal Mustapha¹, Mohd Anuar²

FDMP-Fluid Dynamics & Materials Processing, Vol.21, No.9, pp. 2289-2304, 2025, DOI:10.32604/fdmp.2025.066983 - 30 September 2025

Abstract A pump operating as a turbine (PAT) is a type of hydraulic machine capable of functioning both as a pump and as a turbine by reversing the flow direction. The pump-as-turbine (PAT) approach presents an effective method of hydropower generation, particularly suitable for addressing the increasing global energy demands in rural and remote areas. In addition to its adaptability, PAT-based micro-hydropower systems typically incur lower operating costs than conventional hydrodynamic turbines, despite requiring higher initial investment. Recent research has focused on integrating PATs into pipe distribution systems to harness untapped hydraulic energy. This study presents… More >

Orkhan Jafarli^*

Energy Engineering, Vol.122, No.9, pp. 3595-3608, 2025, DOI:10.32604/ee.2025.067982 - 26 August 2025

Abstract This study investigates the feasibility and efficiency of geothermal energy for heating applications in Azerbaijan, with a specific focus on the Khachmaz region. Despite the country’s growing interest in sustainable energy, limited research has addressed the potential of ground-source heat pump (GSHP) systems under local climatic and soil conditions. To address this gap, the study employs GeoT*SOL simulation to evaluate system performance, incorporating site-specific parameters such as soil thermal conductivity, heating demand profiles, and regional weather data. The results show that the GSHP system achieves a maximum seasonal performance factor (SPF) of 5.62 and an… More >

Ziqiang Man¹, Lei Zhao², Zheng Tao¹, Shiming Cheng², Wei Yan¹, Gaoyue Zhong¹, Yu Lu¹, Wenming Zhang³, Li Zhang^3,*

Energy Engineering, Vol.122, No.9, pp. 3555-3572, 2025, DOI:10.32604/ee.2025.067027 - 26 August 2025

Abstract With the rapid integration of renewable energy sources, modern power systems are increasingly challenged by heightened volatility and uncertainty. Doubly-fed variable-speed pumped storage units (DFVS-PSUs) have emerged as promising technologies for mitigating grid oscillations and enhancing system flexibility. However, the excitation converters in DFVS-PSUs are prone to significant issues such as elevated common-mode voltage (CMV) and neutral-point voltage (NPV) fluctuations, which can lead to electromagnetic interference and degrade transient performance. To address these challenges, an optimized virtual space vector pulse width modulation (OVSVPWM) strategy is proposed, aiming to suppress CMV and NPV simultaneously through coordinated… More >

Muhammad Farooq Siddique¹, Saif Ullah¹, Jong-Myon Kim^1,2,*

CMC-Computers, Materials & Continua, Vol.84, No.2, pp. 3577-3603, 2025, DOI:10.32604/cmc.2025.065326 - 03 July 2025

Abstract Centrifugal Pumps (CPs) are critical machine components in many industries, and their efficient operation and reliable Fault Diagnosis (FD) are essential for minimizing downtime and maintenance costs. This paper introduces a novel FD method to improve both the accuracy and reliability of detecting potential faults in such pumps. The proposed method combines Wavelet Coherent Analysis (WCA) and Stockwell Transform (S-transform) scalograms with Sobel and non-local means filters, effectively capturing complex fault signatures from vibration signals. Using Convolutional Neural Network (CNN) for feature extraction, the method transforms these scalograms into image inputs, enabling the recognition of More >

Xiao Sun¹, Huifan Huang¹, Yanjuan Zhao^2,*, Lianghuai Tong^3,*, Haibin Lin³, Yuliang Zhang⁴

FDMP-Fluid Dynamics & Materials Processing, Vol.21, No.6, pp. 1261-1298, 2025, DOI:10.32604/fdmp.2025.064329 - 30 June 2025

Abstract The reverse operation of existing centrifugal pumps, commonly referred to as “Pump as Turbine” (PAT), is a key approach for recovering liquid pressure energy. As a type of hydraulic machinery characterized by a simple structure and user-friendly operation, PAT holds significant promise for application in industrial waste energy recovery systems. This paper reviews recent advancements in this field, with a focus on pump type selection, performance prediction, and optimization design. First, the advantages of various prototype pumps, including centrifugal, axial-flow, mixed-flow, screw, and plunger pumps, are examined in specific application scenarios while analyzing their suitability… More >