Applied Mechanics and Materials Vol. 525

Abstract: This paper points out that the traditional design method of multi blade centrifugal fan are great uncertainty in selecting the structure parameters: lead to many design results, do many tests. Internal flow field of multi blade centrifugal fan was simulated with the computational fluid dynamics software Fluent, and the numerical results are analyzed. Comparison of the numerical results with the test results shows that numerical simulation has good accuracy and reliability. The design program and a design example is gived according to the design theory of multi blade centrifugal fan. Method is verified by numerical simulation for the example. Test results show that the design program is reliable.

Abstract: To investigate flow characteristics by high speed video systems, experimental study was conducted to gas-liquid two-phase flow in horizontal round small tube with diameter of 5.5 and 2.6 mm, the typical flow pattern images were obtained, but stratified flow of the conventional size horizontal channel had not been discovered. Gas and liquid superficial velocities range from 0.1 to 100 ms^-1, and 0.01to 10.0 ms^-1 respectively. Flow patterns for co-current flow of air-water mixtures in horizontal round tubes are determined by high-speed video analysis to develop flow regime maps and the transitions between these flow regimes. Comparisons with the relevant literatures show that diameter and surface tension effects play an important role in determining the flow patterns and transitions between them.

Abstract: Ultrasonic strengthening separation is a contactless separation technique, it is widely used in industrial processes, environmental assessment, biochemical analysis, clinical diagnosis and other fields. In this article, we deduced microparticle clustering in Z and X direction Coordinate equation, discussed in detail the various factors influencing particles equilibrium position in the liquid medium.

Abstract: The paper presents the hermetic thermistor sensor packaging with 12.8mm×9.6mm used in exothermic reactions detection. The mechanical analysis was conducted including the germanium (Ge) window stress and deformation caused by process stress and vacuum effects. The maximum deformation of Ge window is about 281.5μm and the stress intensity is about 650.19MPa. YbF3 with the thickness of 1.36μm and 1.09μm are used as double-layer antireflection films to weaken the reflection incidents. The transmission is 87.82% for 8-14μm wavelengths as calculated. The paper also presents the influence of vacuum environment on detectors performance. The results suggest that the temperature response approaching to theoretical value when the chamber pressure is lower than 0.01 mbar. At last, this work illustrates the process flow and fabrication details of the packaging devices.

Abstract: The working principle of a Wireless Power Transmission technology (WPT) system and compensated capacitance topologies were introduced. Then, based on MATLAB SIMULINK software, capacitance compensated in the primary and secondary winding on the influence of the WPT system performance were studied. The results show that the primary compensated capacitance in series can improve the voltage of the load, the primary compensated capacitance in parallel can reduce the primary winding current; the secondary compensated capacitance can also improve the load voltage, but the rate is not obvious; in the SP model, the load voltage and power factor are the biggest, the influence of the variational capacitance in the primary on the output power is bigger than in the secondary

Abstract: The working principle of a Wireless Power Transmission technology (WPT) system of the implantable cardiac pacemaker was introduced. Then, based on Ansoft Maxwell software, the three-dimensional finite element model of the WPT system was established. Finally the influence of some parameters, such as the gap and radial migration of the primary and secondary winding, ferrite core, working frequency on the self - inductance, mutual inductance, and the coupling performance were studied. The results show that with the gap or radial migration increasing, the self- inductance is almost same, but the mutual inductance and coupling coefficient decrease; the ferrite core may significantly enhance the inductance and coupling performance; the inductance and coupling coefficient has nothing to do with the working frequency.

Abstract: The image of magnetic field is traditionally obtained by spreading magnetic powder manually or by sparse arrays of magnetic needles, obtaining the images of the magnetic field in different permanent magnet shapes and do repeated tests on the permanent magnet are in need. Based on programmable logic controller (PLC) motion control, the servo control and mechanical system have been built, the control strategy is discussed and the software is programmed. 2D FEM model of a test permanent magnet bar is built. Compared with the FEM simulation results, the system has achieved the goal that spreading magnetic powder quickly and evenly in the appointed area.

Abstract: The influence factors of Photovoltaic (PV) cells characteristics integrated on chip were analyzed based on the fabrication process and the structure of the PV cells and CMOS devices. The results show the substrate doping concentration, the emitter doping concentration, the emitter junction depth and the thickness of device layer directly determine the conversion efficiency, open voltage and the light-generated current of photovoltaic cells. In the emitter doping concentration range of 1×10¹⁹/cm³ to 1×10²¹/cm³ and the substrate doping concentration range of 1.0×10¹⁵/cm³ to 1.0×10¹⁷/cm³, the Photovoltaic cells have batter conversion characteristics. The PV cells were designed based on the analysis results in PC1D, and the conversion efficiency is 9.43%. The Photovoltaic cells and the CMOS devices have batter fabrication technology compatibility integrated on chip.

Abstract: For electric magnetic system which contains permanent magnet, its calculation results often has a low level accuracy when using equivalent circuit method .The calculation method of permanent magnet leakage permeance is the key point and needs to be improved. The leakage permeance calculation formulas of bar type permanent magnet are deduced. The magnetic field simulation method and analytical method for calculating leakage permeance of bar type permanent magnet in open magnetic circuit are investigated based on the finite element method. An example is given and the results are validated by experiment. The methods and results can be used to found the equivalent magnetic model with high accuracy.

Abstract: An inclined contact surface design for Radio Frequency Identification (RFID) interrogator with easy-pick gaps has been developed. Compared with the curved surface and pallet surface, the performance of inclined contact surface has been investigated in the calculated electromagnetic configurations and experimental results. It is found that the inclined contact surface has the improved reliability of data writing of RFID. By experimentally and theoretically analyzing, the improved reliability is considered to be the combined results of the energy coupling configurations and the depressed material contacts effect.