Applied Mechanics and Materials Vol. 733

Abstract: The structure of cast iron specimen and the temperature control unit of the engine coolant ultrasonic cavitation apparatus were improved in this paper. The broken problem of cast iron specimen was solved by split-structure design, which also solved the loose binding problem between specimen and sonotrode. The temperature control unit included a beaker with water circulating jacket, water bath, circulating pump and connection hose. The temperature control unit overcame the difficulty of the temperature control of test coolant solution. More important, the temperature control inside the soundproof box was realized, which avoided the effect of ultrasonic vibration noise on the health of operator. The unit has the characteristics of simple, practical and easy to use.

Abstract: The Propeller Boss Cap Fins (PBCF) is often used to ordinary propeller, a good energy-saving effect being obtained. In order to study the energy-saving mechanism of ducted propeller with PBCF, in this paper, the FLUENT has been taken to simulate the distribution of thrust coefficient, torque coefficient, blade pressure and velocity vector of hub surface at different advance coefficients. By contrasting the results of numerical simulation of hydrodynamic performance of ducted propeller between with fins and without fins, we know that at the low advance coefficient, the ducted propeller with fins will increase the thrust coefficient and decrease the torque coefficient; rising the open water propeller efficiency, improving the efficiency under the premise of the efficiency increase by duct. The existence of fins has changed velocity distribution of water around the hub and made the water that flowed around the propeller hub with propeller rotation direction flow to propeller tail along the fins not gather in the cub, so it weakened the hub vortex.

Abstract: Application of computational fluid dynamics (CFD) in the design of the road sweeper is a new and effective method for the feasibility analysis. By using CFD technology to analyze the flow field of the road sweeper airstream system, we can obtain the characteristic parameters before it is manufactured, so that the analysis and design of the airstream system can be carried out simultaneously. Studies have shown that combining with the specific engineering practice, the application of CFD on the flow field simulation has a certain reference value for the design and optimization of the sweeper airstream system.

Abstract: In order to adapt to new modern car styling, the aerodynamic numerical simulations based on computational fluid dynamics (CFD) are applied to the process of car styling. We received the early modeling design automobile aerodynamic coefficients, pressure distribution, velocity contours and other body outflow field data after the CFD post, combined with these data some advice to improve the aerodynamic drag of the designed car are given. Proposed aerodynamic automobile design method is based on numerical simulations, according to experience in air vehicle dynamics studies.

Abstract: The CAD software was used to establish 3D model of frame of dump truck, and the finite element model was established through Hyper Mesh. The stress distributions of the frame in vertical accelerating, turning, twisting and climbing conditions were computed through finite element software when the dump truck was loaded 80t. The result is consistent with the actual situation of the frame, which proved that the approach of finite element analysis is feasible. And we proposed the improved method of the frame according to finite element results.

Abstract: The principle of the design of the wind-tunnel contraction is introduced; several typical contraction curves provided by former researchers are collected and compared. Using commercial Computational Fluid Dynamics (CFD) software-Fluent: Fluent. The flied quality of different contraction curves using a 3-D axial symmetric k-ε model is compared and some suggestions on the selection of the curves to different requirement are made. Witozinsky curve and Batchelor-Shaw curve prone to counter pressure at the entrance area, serious energy loss, the speed of export poor uniformity. The uniformity of the flow field is a little better of the improved 3-power curve (Xm = 0.5).5-power curve (Xm=0.5, n=7) shows low turbulence degrees, a certain advantage in energy consumption and strong stability.

Abstract: Flat grooved heat pipes, which are especially useful in obtaining a high degree of temperature uniformity on flat surfaces, have been successfully used in the temperature control of electronic systems, however, the mechanisms governing the flow and heat transfer of this kind of heat pipes are still under scrutiny as some reported results cannot be reproduced by others or some assumptions have been proven to be unreasonable or ideal. The theoretical and experimental studies on flat grooved heat pipes and introduce work performed on modeling flat grooved heat pipes are reviewed in this paper.

Abstract: The aero-engine is the core part of the aircraft, which plays a very critical role in aviation safety and economy. The engine fleet management is a workable management tool, can be used in airline route operation, with the goal of improving the engine time between shop visits and optimizing maintenance costs, while maintaining the reliability of the engine in service.

Abstract: We propose a test system which is easy to operate, and has high degree of automation, and introduce its detail of operating principle and test methods, and according to the requirements of the hydraulic jumbler performance, mainly test the rotational speed, flow, torque and propulsion and other performances of the hydraulic bolt rig. The measured results were analyzed and studied, and then the measures for improvement were proposed.

Abstract: This paper researches on the non-contact online detection of concentricity error, which mainly focus on the structural principle of the measurement system and the concentricity error evaluation methods. The paper using the method of projection, converting the three-dimensional model to a two-dimensional model and evaluating coaxially error. And it is validated by the simulation of MATLAB. In theory, the proposed measurement system can measure geometric tolerance, including coaxially error, cylindricity error, circularity error, etc.