Le Anh Duc^a , Pham Van Kien^b,*, Nguyen Thanh Tan^b, Doan Thanh Son^b, Nhanh Van Nguyen^c, Ngoc Xuan Nguyen^d

Frontiers in Heat and Mass Transfer, Vol.20, pp. 1-6, 2023, DOI:10.5098/hmt.20.25

Abstract This study focused on the heat and mass transfer in radio (RF) assisted heat pump (HP) drying of carrots. The experimental drying of carrot by RF assisted HP drying method was conducted to evaluate the effect of RF power on drying efficiency including drying rate and heating rate. The input drying parameters were drying air temperature of 45oC, drying air velocity of 2.5 m/s and RF power of 0, 0.5 and 1.5 kW, in which, RF power of 0 was corresponding to HP drying method. The experimental drying results showed that in RF assisted HP drying method, the drying rate… 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 to reach stability is lagged,… More >

Yu-Liang Zhang^a,* , Dong-Yang Wu^b, Hai-Bing Cai^c, Can-Fei Wang^c, Fei-Wu^c, Shao-Han Zheng^d

Frontiers in Heat and Mass Transfer, Vol.20, pp. 1-5, 2023, DOI:10.5098/hmt.20.11

Abstract In this paper, based on the Mixture model, the numerical computations of the internal flow field in a sewage pump are carried out. Through numerical simulation, the turbulence flow characteristics in the sewage pump are obtained. Results show that when the particle diameter is 0.10 mm, the solid-phase concentration on the volute surface is high, and the wear is more severe. When the particle diameters are 0.15 mm and 0.20 mm, the solid-phase concentration on the volute surface is significantly higher, especially when the over-current cross-section enlarges constantly. More >

M. El-Bayoumi^a,†, A. M. Abouel-Fotouh^a, Amal El Berry^a

Frontiers in Heat and Mass Transfer, Vol.20, pp. 1-6, 2023, DOI:10.5098/hmt.20.8

Abstract Ram pumps employ renewable energy in the form of water head to pump water, but they have performance issues that require difficult on-site testing and tuning, hence limiting their application. The current research developed a low-cost lab-scale testing system for small ram pumps’ performance evaluation, tuning and leak testing. The developed system is made from available, low-cost, sensors and components. It conserves test water by setting the supply head through continuous circulation of water. The system was tested on a low-cost small sized ram pump, specially built using plumbing components. Test results demonstrated the capacity of the developed testing system. More >

Siwei Han^1,*, Xianglong Li², Wei Zhao¹, Linyu Wang¹, Anqi Liang², Shuang Zeng²

Energy Engineering, Vol.120, No.6, pp. 1421-1444, 2023, DOI:10.32604/ee.2023.027094

Abstract Photovoltaics, energy storage, direct current and flexibility (PEDF) are important pillars of achievement on the path to manufacturing nearly zero energy buildings (NZEBs). HVAC systems, which are an important part of public buildings, play a key role in adapting to PDEF systems. This research studied the basic principles and operational control strategies of a DC inverter heat pump using a DC distribution network with the aim of contributing to the development and application of small DC distribution systems. Along with the characteristics of a DC distribution network and different operating conditions, a DC inverter heat pump has the ability to… More >

Qunbiao Wu¹, Zhen Wang^1,*, Haifeng Fang¹, Junji Chen¹, Xinfeng Wan²

Computer Systems Science and Engineering, Vol.46, No.1, pp. 961-979, 2023, DOI:10.32604/csse.2023.036239

Abstract For surface defects in electronic water pump shells, the manual detection efficiency is low, prone to misdetection and leak detection, and encounters problems, such as uncertainty. To improve the speed and accuracy of surface defect detection, a lightweight detection method based on an improved YOLOv5s method is proposed to replace the traditional manual detection methods. In this method, the MobileNetV3 module replaces the backbone network of YOLOv5s, depth-separable convolution is introduced, the parameters and calculations are reduced, and CIoU_Loss is used as the loss function of the boundary box regression to improve its detection accuracy. A dataset of electronic pump… More >

Wenbin Luo^1,*, Lingfeng Tang¹, Yuting Yan², Yifang Shi¹

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.4, pp. 869-899, 2023, DOI:10.32604/fdmp.2022.022280

Abstract The aim of the study is to determine the optimal structural parameters for a plastic centrifugal pump inducer within the framework of an orthogonal experimental method. For this purpose, a numerical study of the related flow field is performed using CFX. The shaft power and the head of the pump are taken as the evaluation indicators. Accordingly, the examined variables are the thickness (S), the blade cascade degree (t), the blade rim angle (β1), the blade hub angle (β2) and the hub length (L). The impact of each structural parameter on each evaluation index is examined and special attention is… More >

Surendrababu Kuppusamy^1,*, Prabhahar Muthuswamy², Muthurajan Kumarasamy³, Sendilvelan Subramanian⁴

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.4, pp. 1003-1014, 2023, DOI:10.32604/fdmp.2022.022262

Abstract Biodiesel fuel is a potential alternative energy source for diesel engines due to its physiochemical characteristics relatively similar to those of traditional diesel fuel. In this study, the performance, emission, and combustion features of a mono cylinder DI diesel engine are assessed using 20% Pumpkin seed methyl ester (PSOME20) and considering varying injection pressures (200, 220, 240, and 260 bar). The considered Pumpkin seed oil is converted into pumpkin biodiesel by transesterification and then used as fuel. The findings demonstrate that the Brake Thermal Efficiency (BTE) of PSOME20 can be raised by 1.68%, and the carbon monoxide (CO), hydrocarbon (HC),… More > Graphic Abstract

Rabeb Toujani, Nahla Bouaziz^*

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.4, pp. 991-1001, 2023, DOI:10.32604/fdmp.2022.022239

Abstract A hybrid heat pump (compression/absorption) with an integrated thermal photovoltaic unit is studied. The considered working fluids are organic mixtures: R245fa/DMAC and R236fa/DMAC, chosen for their low Global Warming Potential. The main objective is the optimization of energy efficiency in order to minimize the environmental impact through the implementation of a sustainable strategy. It is shown that Exergy Analysis itself is a valuable tool in energy integration. Within the imposed framework of minimizing total annual costs, entropy analysis can be instrumental in determining the optimal plant concept, optimizing energy conversion and use, and improving profitability. The present results are discussed… More >

Yanliang Qiu^1,2, Bin Xiong^1,2, Zhe Hou^1,2,*, Lin Luo³

Energy Engineering, Vol.119, No.6, pp. 2243-2254, 2022, DOI:10.32604/ee.2022.021322

Abstract The shrink fit retaining ring is currently the easiest to install and the most widely used end fixed for structure AC excitation variable speed generator-motor rotor end windings. However, the current research on the effect of high strength sealing on the ventilation and heat dissipation performance of the end is not enough. In this paper, based on the actual structural parameters and periodic symmetry simplification, the three-dimensional coupled calculation model of fluid field and temperature field is established. After solving the fluid and thermal equations, the influence of the length of rotor support block, the height of rotor support block,… More >