中國機械工程學刊/Journal of the Chinese Society of Mechanical Engineers
中國機械工程學會,正常發行
選擇卷期
- 期刊
Incremental forming is a new and multipurpose type of prototype manufacturing method where a small forming tool, following a certain tool path, applies localized pressure to a sheet metal. In this study incremental formability of DC01 which widely used in industry is experimentally researched. In the experimental studies, specimens in a shape of frustum cone are formed. Alongside the experimental studies, by using finite element model, sheet thickness variations are investigated. Feedrate, depth of increment and forming tool diameter, which has a direct effect to the limit forming angle and sheet thickness distribution are taken as parameters. In experiments carried out by using 0.5 mm increment and 1000 mm/min feedrate for DC01 sheet with a thickness of 1.18mm, 64° limit forming angle is reached. Corresponding results are compatible with finite element analysis results. Specimen's thickness is reduced by 65% with 64° limit forming angle and minimum sheet thickness of 0.4 mm is achieved.
- 期刊
The presence of downstream curvature can affect the blood flow in artery leading to complicated hemodynamics. Thus, the current study is focused to explore the effect of downstream curvature of artery wall on the severity of stenosis by assessing the Fractional Flow Reserve, Lesion Flow Coefficient and Pressure Drop Coefficient under various downstream curvature angles in coronary artery. Computational fluid dynamics (CFD) of hyperemic flow in curved arteries was performed with various downstream curvature angles (0^0 30^0 60^0 90^0 and 120^0) subjected to three different blockage (70%, 80% and 90%) area stenosis (AS). It is discovered that flow resistance caused by stenosis increases further due to the downstream curvature of artery. The FFR decreased by 5.4%, 8.6% and 13.1% for 70%, 80%, and 90%AS respectively as the downstream curvature of artery increased from 0^0 to 120^0. The increase in CDP and decrease in LFC was found as the downstream curvature increased from 0^0 to 120^0. The differences in diagnostic parameters FFR, CDP and LFC shows that misinterpretation could be possible while evaluating the functional significance of stenosis, so the downstream curvature must be contemplated while evaluating the importance of stenosis as an additional parameter for FFR.
- 期刊
Air dehumidification using desiccants is an important unit operation in drying heat sensitive products like herbs to enhance the preservation properties close to fresh condition after drying. In this present study, an attempt is made to optimize the process parameters on the adsorption rate in the packed bed solid desiccant dehumidifier using molecular sieve 13X desiccant by using Taguchi method. An experimental setup is developed with a filter, flow regulator, on line and off line towers for adsorption and desorption and flow control valve. The effect of process air entry pressure at adsorption tower, desiccant mass and purge air flow rate for desorption tower are studied to evaluate the adsorption performance. A special design of orthogonal arrays obtained in Taguchi’s method is used for the experimentation to study all the parameters with minimum number of experiments. MATLAB genetic algorithm is employed to enhance the parametric optimisation. Statistical results show that the process air entry pressure at adsorber entry is the most influencing parameter compared to desiccant mass, and purge air flow rate for desorption tower for the dehumidification system. The predicted value of response by both the tools is very close to each other, and the fitness function can be taken as the basis for the design of dehumidification system.