ENGINEERING NEWS IN BRIEF
Issued by the Asian TOP Panel, July 2008
The Chinese Mechanical Engineering Society (CMES)
The Institution of Engineers, Indonesia (PII)
The Japan Society of Mechanical Engineers (JSME)
The Korean Society of Mechanical Engineers (KSME)
According to the agreement made in the 2nd Asian TOP Panel Meeting,
the ENGINEERING NEWS IN BRIEF (E-mail newsletter) has now been edited
by the JSME for the year 2008.
1) Application of Laser Induced Fluorescence Method on VOCs
(Volatile Organic Compounds) Measurement (Source: JSME)
2) Effect of intracranial stent on blood flow in cerebral aneurysm (Source: JSME)
3) High-speed, high-precision 5-axis machines achieved with the Direct Drive Motor (Source: JSME)
4) Combustion Improvements on Automotive Diesel Engines (Source: JSME)
5) Active Flying-height Control of Magnetic Head Slider using MEMS Thermal Actuator (Source: JSME)
6) Practical Evaluation Method for Cutting Performance by Ball END Milling using 3D-CAD (Source: JSME)
7) Motion Control of a Precise Wafer Stage (Source: CMES)
8) Structure Design of the Beijing Spectrometer III Beam Pipe (Source: CMES)
9) Theory and Experiment on the Viscous Heating of Fluid Damper under Shock Environment (Source: CMES)
10) Analytical Method to Analyze the Tolerance Effect on the Vehicle Ride Comfort (Source: KSME)
11) A Study on Oxy-Fuel Combustion System with Multi-Jet Burner - Numerical Simulation with PDF Combustion Model (Source: KSME)
12) The Flow Characteristics Around Airfoil Moving Reciprocally in a Channel
1) Application of Laser Induced Fluorescence Method on VOCs (Volatile Organic Compounds) Measurement
Department of Mechanical System Engineering, Graduate School of
Engineering, Gunma University
Volatile organic compounds (VOCs) are organic chemical compounds emitted from the paints or preservative materials. The VOCs are molecules related to the sick building syndrome. Recently, a lot of studies have been carried out for the reduction techniques of VOCs. Laser induced fluorescence (LIF) technique was used as a powerful tool for the combustion diagnostics, because it is able to detect the molecules selectively. In this report, the LIF technique was applied for the measurement of VOCs. By using this technique, spatial distributions of VOCs concentrations on a painting surface could be visualized. It was found that the fluorescence emitted from the water-based lacquers was low compared with that of the acrylic and enamel paints.
2) Effect of Intracranial Stent on Blood Flow in Cerebral Aneurysm
Makoto OHTA, Tohoku University
One of the current hot topics of cerebral aneurysm (CA) is "Image Guided Minimally Invasive Treatment (IGMIT)". Rupture of CA is one of the severe diseases and the quality of life may depend on the treatments before rupture or just after rupture. Intracranial stent (ICS) is one of the endovascular devices to remodel parent artery. Recent studies reveal that ICS may have a capability for reducing flow into aneurysm as a flow diverter. To confirm this capability, we developed a method of computational fluid dynamics (CFD) simulation using realistic geometries of a CA geometry from 3DRA and of a ICS from micro-CT. Virtual Intracranial Stent Challenge (VISC) is an active group for promoting the integration of treatment and CFD.
Biomodeling is a tissue model with 3-D reconstruction and you can handle it to check the geometry. With mechanical properties, the biomodeling can be useful for training of therapy, and pre-operation called as functional biomodeling (FB). FB based on Poly (vinyl alcohol) hydrogel has been developed and promotes the training of stent implantation.
Other topics for CA such as simulation of catheter movement, or detecting the flow speed using x-ray, will lead and improve the IGMIT.
3) High-speed, high-precision 5-axis machines achieved with the Direct Drive Motor
Naoshi TAKAYAMA, Mori Seiki Co.,Ltd
In recent years, the demand for 5-axis machines and multi-axis machines has been growing rapidly, with the aim of increasing productivity.
In the conventional drive system for 5-axis machines' rotary axes, gears are used to transmit power from the servo motor to the rotary axes.
We have developed machining centers which use Direct Drive Motors for their rotary axes. As a result, we confirmed that there have been dramatic improvements in motion accuracy, positioning time, etc.
4) Combustion Improvements on Automotive Diesel Engines
Teruo NAKADA, ISUZU Motors Limited
Current status and future prospects regarding diesel engine combustion improvements are discussed with focusing new concepts to be expected to apply for the tougher regulations of exhaust emissions and fuel economy scheduled in 2009-2015 timeframe.
Various innovative technologies have already been applied on mass produced diesel engines for successful improvements not only on exhaust emissions reduction but also on higher output, quiet operation, better fuel economy and reduced CO2 emission. Particulate emission has also been reduced to the negligible level thanks to the diesel particulate filter, which is now installed mostly on vehicle selled in developed nations.
Further exhaust emissions requirements are focued on NOx and CO2 reduction with keeping very low PM emission. One option is to introduce deNOx aftertreatment system, such as SCR catalyst system, and the other is to improve diesel combustion.
Regarding the innovative combustion improvement for reducing NOx and PM simultaneously, two major approaches are proposed, namely "Low temperature pre-mixed combustion" and "High boost, high EGR rate and high injection pressure supported combustion". In order to realize those combustion, though conceptual requirements are establised, there are still numerous hurdles to introduce in mass produced diesel vehicles.
5) Active Flying-height Control of Magnetic Head Slider using MEMS Thermal Actuator
Masayuki KURITA, Hitachi Global Storage Technologies Japan, Ltd.
As the recording density of hard-disk drives (HDDs) has rapidly increased, the flying height of magnetic head sliders has to be decreased to less than 10 nm. The wide distribution band of flying heights caused by wide manufacturing tolerances and environmental variations, was the largest obstacle to reducing the flying height. To reduce the distribution tolerances, we have developed a thermal flying-height control (TFC) technique. This technique can be used to adjust the flying heights of sliders on demand by means of a built-in thermal-actuator. This new technique enhances the performance and improves the production yield of HDDs.
This paper also addresses new technological challenges and reviews potential solutions.
6) Practical Evaluation Method for Cutting Performance by Ball END Milling using 3D-CAD
Hiroyasu IWABE, Niigata University
Keisuke SHIMIZU, Seiwa Mold Co.
Minoru SASAKI, CS. Technical Co.
The cutting process of a ball end mill is very complex due to the existence of a cutting
edge on the hemisphere surface. Then, in this study, at first the modeling of a cutter, an
edge, a rake surface and a workpiece with an inclined surface are carried out using 3D-CAD.
Secondly, the chip body which will be removed is defined by the interference of the tool
and the workpiece models and the chip area which is changed during the machining
process is calculated by the interference of the rake surface and the chip body. The
influence of the cutting method and the direction of pick feed on the behavior of the chip area and the influence of the inclination angle of the machined surface on the maximum chip area are shown. And, the evaluation value Ed for cutting performance with the multiple by the chip area and the distance from the spindle axis to the center of gravity of the chip area is proposed and compared to each calculated value. The evaluation value of the condition by step up pick feed, ¿=20shows the minimum, so a good cutting performance would be expected from these cutting conditions.
7) Motion Control of a Precise Wafer Stage
Zhang Shangying, Chen Xuedong, Zhao Hui, Yan Tianhong
Huazhong University of Science and Technology
Shanghai Micro-electronics Equipment Co. Ltd.
Motion control system of an ultra precision wafer stage with application to integrated circuit production was presented. Configuration and master / slave control principle of ultra precision wafer stage were introduced. By adopting merits of both coarse and fine stage, a desired motion control system having the capacity of large workspace with high resolution of motion was enabled. Identification method of mechatronics system such as ultra precision wafer stage was pictured and done based on closed-loop control. The automated synthesis procedure of parallel PID controller and robust controller were developed using loop shaping techniques. Force decoupling strategy was developed under the consideration of reality in practice. The simulation result shows that the positioning precision achieves to 10 nanometers in the ultra precision wafer stage using dual stage.
Key words: ultra precision; wafer stage; master / slave control; force decoupling; nanometer
8) Structure Design of the Beijing Spectrometer III Beam Pipe
Zheng Lifang, Ji Quan, Wang Li, Li Xunfeng, Xu Shaowang, Dong Sujun
Zhao Libin, Liu Jianping
University of Science and Technology Beijing
Chinese Academy of Sciences
The Beijing spectrometer III (BESIII) beam pipe is in the center of the BESIII, which is the detector of the upgrade project of Beijing electron and positron collider (BEPCII). Electrons and positions collide in the BESIII beam pipe. According to the demands of the BEPCII, a key program of Chinese Academy of Sciences, the BESIII beam pipe is designed based on the finite elements analysis. The BESIII beam pipe is installed in the inner cylinder of the BESIII drift chamber. As a vacuum tube, the BESIII beam pipe is designed as 1000 mm in length, 63 mm in inner diameter and 114 mm in outer diameter, respectively. The BESIII beam pipe consists of a central beryllium pipe cooled by EDM-1, the oil No.1 for electric discharge machining, and two extended copper pipes cooled by deionized water (DW). The three parts are jointed by vacuum welding. Factors taken into account in the design are as follows: 1) the wall thickness of the central beryllium pipe should be designed as small as possible to reduce the multi-scattering and improve the particle momentum resolution. And the wall thick ness of the extended copper pipe should be designed as large as possible to protect the detectors from the backgrounds; 2) the BESIII beam pipe must be sufficiently cooled to avoid the damage and prevents its influence to the BESIII drift chamber (DC) operation. The inner surface temperature of the DC inner cylinder must be maintained at 293+/-2 K; 3) the magnetic permeability of the materials used in the BESIII beam pipe must be less than 1.05 H/m to avoid large magnetic field distortions; 4) the static pressure of the vacuum chamber of the BESIII beam pipe must be less than 800 ÊPa. the simulating results show that the designed structure of the BESIII beam pipe satisfies the requirements mentioned above. The structure design scheme is evaluated and adopted by the headquarters of BEPCII.
Key words: beam pipe; Beijing spectrometer III; structure design; Beijing electron and positron collider II
9) Theory and Experiment on the Viscous Heating of Fluid Damper under Shock Environment
Chu Deying, Zhang Zhiyi, Wang Gongxian, Hua Hongxing, Wang Yu
Shanghai Jiaotong University
A specially designed fluid damper used as negative shock pulse generator in the shock resistance test system to dissipate the shock input energy in transient time duration is presented. The theoretical modeling based on the three-dimensional equation of heat transfer through a fluid element is created to predict the viscous heating in the fluid damper under shock conditions. A comprehensive experimental program that investigates the problem of viscous heating in the fluid damper under different shock conditions is conducted on the shock test machine to validate the analytical expression. Temperature histories for the fluid within the damper at two locations, the annular-orifice and the-end-of stroke of the damper, are recorded. The experimental results show that the theoretical model can offer a very dependable prediction for the temperature histories in the damper for increasing input velocity. The theoretical model and experimental data both clearly indicate that the viscous heating in the damper is directly related to the maximum shock velocity input and the pressure between the two sides of the piston head.
Key words: fluid damper; negative shock pulse generator; viscous heating; shock conditions
10) Analytical Method to Analyze the Tolerance Effect on the Vehicle Ride Comfort
Beom Seok Kim, Hong Hee Yoo
Analytical method to analyze the tolerance effect on the vehicle ride comfort is suggested in this paper. Ride comfort is one of the most important performance indices which decide the vehicle design quality. In general, the ride comfort is affected by the variations of parameters of a vehicle model. Therefore, the effects of the parameters on the ride comfort need to be evaluated statistically based on the whole-body vibration of the vehicle. In this paper, weighted RMS values of the acceleration PSD of a seat position are used to define the ride comfort. The equations of motion and the sensitivity equations are derived based on a 5-DOF vehicle model. By employing the sensitivity information of the acceleration at the seat position, the tolerance effect on the vehicle ride comfort could be effectively analyzed.
Key words: Tolerance Analysis, Sensitivity, Ride Comfort, Weighted RMS, Vehicle Model, Whole-Body Vibration
11) A Study on Oxy-Fuel Combustion System with Multi-Jet Burner - Numerical Simulation with PDF Combustion Model
Hyeon Jun Kim, Wonyoung Choi, Soo Ho Bae, Jung Goo Hong, Hyun Dong Shin
The characteristics of nonpremixed oxy-fuel flame in a multi-jet burner were experimentally and numerically investigated. The overall flow rate of fuel and oxygen was fixed, and the oxygen feeding ratio (OFR) was varied by 0.25, 0.5, and 0.75. The results of numerical simulation were compared with the measured results which are temperature profile and direct flame observation. The probability density function (PDF) model was applied accounting to the description between turbulence and chemistry, and standard k-Ã model was used for turbulent flow field. Equilibrium assumption is very reasonable due to fast chemistry of the oxy-fuel combustion. Thus, the equilibrium calculation based on Gibbs free energy minimization was guaranteed to generate the solution of the oxy-fuel combustion. The result was obtained by numerical simulation. The predicted radial temperature profiles were in good agreement with the measured results. The flame length was shorten and was intensified with the decrease of OFR because the mixture of fuel and oxidizer are fast mixed and burnt. The maximum temperature became lower as the OFR increased, as a consequence of large flame surface area.
Key words: Oxy-Fuel Flame, Multi-Jet Burner
12) The Flow Characteristics Around Airfoil Moving Reciprocally in a Channel
Ki-Deok Ro, Kwang-Seok Kim, Jong-Hyeon Kim
Gyeongsang National University
The Flow characteristics of a ship's propulsion mechanism of Weis-Fogh type, in which a airfoil(NACA0010) moves reciprocally in a channel, were investigated by the PIV. Velocity vectors and velocity profiles around the operating and stationary wings were observed at opening angles of ¿=15 and 30, velocity ratios of V/U= 0.5 to 1.5 and Reynolds number of Re= 5,200 to 10,000. As the results the fluid between wing and wall was inhaled in the opening stage and was jet in the closing stage. The wing in the translating stage accelerated the fluid in the channel. And the flow fields of this propulsion mechanism were unsteady and complex, but those were clarified by flow visualization using the PIV.
Key Words: Fluid Machinery, Propulsion Mechanism, Flow Visualization, PIV, Unsteady Flow
Editor : International Affairs Committee
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