Advanced Materials Research Vols. 631-632

Abstract: Interaction between laser plasma and bow shock wave in front of supersonic vehicle is analysized. Physical and mechanical model of laser plasma energy being deposited in supersonic fluid field is established and computational code is programmed. Process of drag reduction by laser plasma in supersonic vehicle is simulated numerically, and the mechanism of laser plasma reducing drag is disclosed. Simulated results are compared with relative references’, which agree well with each other. It is illuminated that drag reduction by laser plasma can be studied by the established model and code.

Abstract: The safety performance of bridge type grab ship unloaders are the main factors in the normal operation of a bulk cargo wharf. This article made a research of the stress test technology on the use of safety assessment on the structure of the bridge type grab ship unloader, through the dynamic stress test of ship unloader key parts of the structure under the use of the condition, analysis bridge type grab ship unloader safety performance is at ordinary times and maintenance and inspection needs to focus on the dangerous site.Stress test shows that the Maximum compressive stress is Point 7, its maximum dynamic compressive stress is 82.5MPa; while the maximum tensile stress occurs at point 11, its maximum dynamic tensile stress of 72.5MPa. After 17 years used, The force main parts (except former trolleys) of the ship unloader are basically the same as its design value.

Abstract: The Vivaldi antenna is a kind of wide band antenna, which is widely used in many wide band electronic systems. This paper designed and fabricated a specific antipodal Vivaldi antenna (AVA) for practical application. The operating frequency range of fabricated AVA is from 2 GHz to 11GHz. The length and width of the fabricated AVA are 92.7millimeter and 110.4millimeter, respectively. A practical AVA was fabricated according to simulation parameters. The experimental results of the AVA are provided and analyzed. For the fabricated AVA, the measured average voltage standing wave ratio (VSWR) is 2 and gains are higher than 0 dB within the operating frequency range. Meanwhile, the wide beam performances are also observed. The experimental research on the AVA can be as a technical reference for the design and implementation of other Vivaldi antennas.

Abstract: Thermal flow simulation can be used to study the fluid flow and heat transfer for a wide variety of engineering equipment. Flow simulations with the advent of computer architectures with superfast processing capabilities are rapidly emerging as an attractive alternative to conventional thermal flow analysis which is either too restrictive or expensive. In thermodynamic applications, increase of thermal efficiency of heat exchangers (i.e. radiators, cooling towers, condensers, intercoolers) is essential for compact design and improving whole cycle efficiency thus improving economic viability of the system. This paper outlines the process taken to optimize the geometry of conventional heat exchanger. Models were drawn into Solidworks and a computational domain was created. Solidworks Thermal Simulation was used to iterate toward a converged solution with the goal of obtaining a better efficiency of the heat exchanger. The results are analyzed and compared between two differently designed heat exchangers to find out the improvements. These practices were detailed in hopes that further research would use the ground work laid out in this paper to redesign existing heat exchangers.

Abstract: Based on the mass flow measurement by tunable diode laser absorption spectroscopy (TDLAS), the process of air flow measurement was modeled and simulated. Using the Gridgen software, we drew the model inlet grid. And we used fluid calculation program to calculate gas condition in the inlet model. Under the set conditions, we got the mass flow of the model. Compared the mass flow which is measured by the TDLAS technology with the calculated data, we can obtain the measurement accuracy of TDLAS.

Abstract: CODAD (Combined Diesel and Diesel) has been widely used in marine propulsion shafting, but there were few researches about the device for shaft coupling vibration. In this paper, based on the independent design multi-functional test bench of the marine power plant, the coupling vibration calculation method of the test bench was established for the gearbox output helical gear through the theory analysis. Then the calculation method was proved feasibility by compared the torsional vibration measured data and two methods of calculating results.

Abstract: Combining the thought of correlation degree analysis in the theory of grey, use of particle swarm algorithm, seeking it’s individual extreme value and global extreme value, and puts forward to the goal of mathematical model about more gray particle swarm optimization algorithm is presented, the algorithm is applied to speed reducer hoisting mechanism in the optimization of parameters. The optimization results show that the optimal parameters, than the original design of parameters for satisfactory results show the particle swarm optimization algorithm is used for gray hoisting mechanism optimized parameter design of gear reducer is effective and feasible.

Abstract: In this paper, the two main reasons are introduced such as great varying range of echo signal power and pulse signal error, which affect the pulse laser ranging accuracy and analyzed on the base of the pulsed laser range finding method. For them, the methods are provided that the AGC technology in the receiving circuit is adopt to extend the dynamic range of the receiver, and gain the high precision receiving pulse signal by using high-speed voltage comparator. Then the problems of great varying range of echo signals caused by different measuring distance and contacting the timing circuit are resolved efficiently.

Abstract: In this paper, numerical simulation was performed to comparatively research the thermally driven heat transfer phenomenon of the four kinds of small-size circular channels in the gravitational field. Four kinds of the channels were headed at one end and cooled at the other. At the same time, the thermal drive of fluid was used to accomplish the heat transfer in a high body-force field. The research results indicate that four kinds of circular channels have the same thermally driven heat transfer rule. Furthermore, the thermally driven heat transfer power can be enhanced with the addition of the circular channels. Therefore, when we utilize micro-cyclic channels to cool turbo-vanes, the adoption of multi-cyclic channel may be a feasible design because the adaptability of fluid can be utilized to enhance the heat transfer.

Abstract: The in-plane mechanical properties of honeycomb paperboard were analyzed and simulated by ANSYS software with finite element analysis method. This paper also explored and optimized finite element modeling method of honeycomb paperboard structure and obtained the equivalent stress distribution maps of honeycomb paperboard in different displacement loads. The mechanical properties and deformation mode of the honeycomb paperboard in the in-plane compression conditions were also analyzed. The results show that longitudinal compressive strength is greater than the lateral compressive strength. The compression deformation mode is different when compressing but appears with the same four stages. The results of finite element analysis have good equivalence with the experimental ones. This paper also revealed the honeycomb paperboard in-plane mechanical properties, deformation and destruction mechanism, further extended the research scope of honeycomb paperboard, and promoted the application of finite element method in the analysis of honeycomb paperboard.