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Centrifugal pump often operates at different working flow rates to meet engineering requirement. To better reveal the transient behavior of centrifugal pump in the process of decreasing flow rate, the finite volume method (FVM), RNG k-ε turbulence model, sliding mesh technology, and user-defined functions (UDF) were employed to simulate the three-dimensional unsteady viscous incompressible flow in a low-specific-speed centrifugal pump during the abrupt valve-off period. The results show that the differences are very obvious between transient and quasi-steady calculations. The velocity is maximum on the wall of hub and shroud, while the velocity is minimum and uniform distribution at middle positions. The transient flow field lags behind the quasi-steady flow field, which may be related to the reasons; namely, kinetic energy cannot convert pressure energy in time. [ABSTRACT FROM AUTHOR]

Nozzle flowmeter is widely used in industry. In this paper, in order to study the influence of different flow rates and inner wall temperatures on the thermal effect and flow field of the nozzle flowmeter, the fluid-solid coupling numerical calculation of the thermal effect and flow field of nozzle flowmeter is carried out under four different flow rates and five different inner wall temperatures. It is found that, with the increase of flow rate, the heat transfer effect of the nozzle flowmeter is weakened under different inner wall temperatures. The pressure distribution in the fluid domain, the dynamic stress, and fluid-induced vibration deformation generated by the fluid of the nozzle flowmeter are less affected by inner wall temperatures. [ABSTRACT FROM AUTHOR]

Intelligent mechanical fault diagnosis has developed very fast in recent years due to the advancement and application of deep learning technologies. Thus, there are many deep learning network models that have been explored in fault classification and diagnosis. However, there are still limitations in research on the relationship between fault location, fault type, and fault severity. In this paper, a novel method for diagnosis of bearing fault using hierarchical multitask convolution neural networks (HMCNNs) is proposed, taking into account the mentioned relationships. The HMCNN model includes a main task and multiple subtasks. In the HMCNN model, a weighted probability is used to reduce the classification error propagation among multitasks to improve the fault diagnosis accuracy. The validity of the proposed method is verified on bearing datasets. Experimental results show that the proposed method is very effective and superior to the existing methods. [ABSTRACT FROM AUTHOR]

A superconducting quadrupole magnet based on the Canted-Cosine-Theta (CCT) type coil with a gradient field of 40 T/m and a bore diameter of 60 mm has been designed for the preresearch of two projects of high intensity accelerator facility (HIAF) and accelerator driven subcritical system (ADS). The magnet is comprised of two-layer coils embedded in the formers and the end plates for locating. The coil formers made of aluminum alloy are machined with grooves according to the drive equations of CCT for placing the wires. The existence of ribs between two adjacent wires can avoid accumulation of the electromagnetic force. It is important to take the mechanical design for the complex structure to avoid tensile stresses on the conductor and confine the stresses within a reasonable value. The stress analysis for the quadrupole magnet has been carried out considering the thermal shrinking due to cool down as well as the electromagnetic force on the coil. This paper reports the detailed stress analysis for the CCT quadrupole magnet structure, discusses the calculating results, and gives a reasonable mechanical design. [ABSTRACT FROM AUTHOR]