An investigation of thermohydraulic performance of a double-pipe heat exchanger with swirl fins were performed by using numerical simulation and single objective optimization method. In this study, the geometric parameters of swirl fins include the ratio of width of inner fin roots to circumference of inner flow passage, the number of fins, the height of fins and the swirl angle of fins were examined. Besides, fixed Reynolds number and constant inlet temperature were assumed for the simulation. ...

The harmonic drive has become a critical component in robotic arms, enhancing their load capacity. Therefore, the harmonic drive's health status affects robotic arms' operational stability. This study focused on diagnosing anomalies in harmonic drives before equipment failure. By artificially creating five common types of faults in harmonic drives and collecting vibration signals with a three-axis accelerometer, this study trained and verified the diagnostic capabilities of nume...

Porous materials are essential in applications like impact absorption, thermal management, tissue engineering, and vibration damping, making their detailed study crucial. Key parameters in pore structure characterization include porosity, pore distribution, types, aperture size, shape, tortuosity, pore size distribution, specific surface area, and permeability. This study numerically simulates the permeability of two Triply Periodic Minimal Surfaces (TPMS) structures—Primitive ...

When an automatic mechanical transmission (AMT) shifts gears frequently, the clutch is repeatedly in the state of slipping, which makes the clutch thermal effects accumulate rapidly. The temperature in the frictional parts rises and spreads after the clutch's frictional work is applied, that needs some moments. To observe the clutch thermal effects and overcome the delay of temperature rise variation on clutch control, this paper proposes a prediction control for clutch tempera...

In order to realize automatic polishing of propeller, dynamic analysis and topological optimization of a propeller polishing machine tool were studied. The machine adopts the design of series clamping robot and auxiliary support arm to cooperate, which retains the advantages of high flexibility of series robot, while the addition of auxiliary support arm improves the stiffness of the clamping robot. The spatial coordinate system of the clamping robot of the propeller polishing ...

To address the problems of complex structure, high cost, and weak stability of the traditional shipboard stabilization platform, this work proposes a series-parallel shipboard stabilization platform, which consists of a series mechanism and a parallel mechanism composite and has the advantages of simple structure, good stability and high control accuracy. In this work, the platform's robustness was analyzed, and experiments on the control accuracy and dynamic characteristics we...

The primary goal of this work is to thoroughly examine the sub cooled boiling phenomena in inclined and vertical pipes. The continuity, momentum, and energy equations for each phase serve as the foundation for the mathematical model. For the conditions of critical heat flux connected to Eulerian two fluid model, the modified RPI model was employed. With the aid of CFD software, ANSYS FLUENT R2021, the mathematical model was resolved. The findings, which include axial profiles of the ...

In this study, the effects of Mach Number and air temperature on high-bypass ratio, separate-exhaust turbofan engine efficiency, and fuel consumption were investigated. A coding method with real data was used and the comparison of results with valid data indicated that the error was below 2%. The results showed that with the increase of Mach Number from 0.1 to about 1.1, the overall efficiency and the propulsive efficiency increased, but the thermal efficiency was constant. Fur...

In this study, theoretically designed single-stage harmonic gear mechanisms with involute tooth profile structures, comprising rigid internal and external gears, were designed and modified according to stress values (gear root bending stress and Hertz contact stress). Two methods were used to achieve harmonic motion: the first involved cutting from the tooth head, and the second involved profile shifting within the tooth structure. Additionally, the effects of four different pres...

Arc welding has low costs and offers high welding efficiency. Visual inspection, the easiest welding inspection method, is prone to human error. This research proposes a convolutional neural network (CNN)-based method for classifying welding defects into the following categories: ‘no defect’, ‘blow hole’, ‘lack of fusion’, ‘incompletely filled groove’, and ‘undercut’. The weld bead was positioned under a camera, and the captured images were transmitted to a computer, which recognised defects in ...