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 หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Simulation of Three Dimensional Liquid-Sloshing Models using C++ Open Source Code CFD Software) ผู้เขียน: เอกชัย ชัยชนะศิริ,  นายชาคริต สุวรรณจำรัส, อาจารย์ สื่อสิ่งพิมพ์:pdf AbstractThe open source computational fl uid dynamic (CFD) codes—open fi eld operation and manipulation (OpenFOAM)—were developed to simulate the three dimensional sloshing of liquid inside moving rectangular tanks. Equations governing the two-phases of fl uid were used in these simulations and the Volume of Fluid method was used to capture the free surface of the liquid sloshing. The fi nite volume method was used to solve these problems. The solutions of the simulations were validated using experiment results based on the free surface height and the pressure developed on the wall of the tanks. It was found that the average error of the surface height and the pressure obtained from the simulations were 2.33% and 6.65%, respectively. |
 ที่มา:สำนักงานกองทุนสนับสนุนการวิจัยหัวเรื่อง:เครื่องมือวัดการเคลื่อนที่ของผิวของเหลวภายในภาชนะบรรจุของเหลวที่ถูกกระตุ้น หัวหน้าโครงการ:นายชาคริต สุวรรณจำรัส, อาจารย์ |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Development of a Wear Testing Machine for Dental Crown Application) ผู้เขียน:Panya Aroonjarattham, นายชาคริต สุวรรณจำรัส, อาจารย์, เอกชัย ชัยชนะศิริ สื่อสิ่งพิมพ์:pdf AbstractA three axes wear testing machine for a dental crown was developed for human tooth application. There were two main sections of the controllers: the application of an AC servomotor (Z-axis) for creating and controlling the force which is used in testing and the application of a step motor (X-axis and Y-axis) for creating and controlling the motion. This study aimed to compare the ability of the controlling force of the AC servomotor on two different surfaces—a smooth fl at surface and a dental crown surface. Three testing cases were considered at frequencies of 0.5, 0.75, and 1 Hz in a range of motion of 1 mm: 1) simulating the force of chewing (0–60 N) and the motion of a circular process, 2) simulating a constant force (60 N) of one way movement in a circular process and 3) simulating a constant force (60 N) of the reciprocating movement in a circular process. The machine was tested using a dental crown, which was made of zirconia, by simulating the force, the motion and the various conditions of the teeth in the oral cavity. The force which occurred in all three axes was measured by the load cell. According to the experiment, the AC servomotor was able to control the force exerted on two different surfaces with nearly similar results. The average force errors on the smooth surface and the dental crown surface were 13.70 and 13.82%, respectively. The root mean square errors of the smooth surface and the dental crown surface were 17.47 and 16.99, respectively. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Diffusion Jet Flame Models Using Open Source Code CFD Software) ผู้เขียน:นายชาคริต สุวรรณจำรัส, อาจารย์, Panya Aroonjarattham สื่อสิ่งพิมพ์:pdf AbstractOpen-source code software (OpenFOAM) based on computational fluid dynamics (CFD) was implemented and applied to simulate the diffusion of a jet flame. The large eddy simulation (LES) of the turbulence combustion model was written using the C++ language. The mixture fraction approach, an infinitely-fast chemistry assumption and radiative heat transfer were combined with this LES model. The finite volume method was performed to solve and simulate diffusion jet flame models under varying methane flow rates and environmental pressures. The results of the jet flame simulation comprising the percentage of maximum burning temperature, the heat release rate and oxygen from the oxygen fraction were defined to be the flame shape for validation with experiments. It was found that the flame length measured using the heat release rate from the results of simulations had the best agreement with the experiments. An average error of less than 5.84% was obtained by a comparison between the developed CFD model and the experiment when the CFD flame length was depicted by the heat release rate. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Finite Element Method for Creep Testing of High Density Polyethylene Lubricant Oil Bottles) ผู้เขียน:นายชาคริต สุวรรณจำรัส, อาจารย์, เอกชัย ชัยชนะศิริ สื่อสิ่งพิมพ์:pdf AbstractStacking is one method for storing many lubricant oil bottles. Bottles on the lower storey may collapse after storage for a long time because of the creep behavior of bottle materials. To avoid bottle collapse, creep testing of the bottle is required to obtain the relation between deformation and the time a bottle is under creep load. This relation can be used to manage the storage time and to improve bottle shape. Unfortunately, the identification of creep resistance for lubricant oil bottles may take more than one month. This is not satisfactory considering the market competition for container products. Therefore, this study used the finite element method (FEM) to simulate the creep behavior of high density polyethylene (HDPE) lubricant oil bottles and compared the experimental results to validate the FEM. Sample 1 L and 6 L bottles with masses of 55 and 310 g, respectively, were tested and simulated. From the results, the overall difference of deformation between the FEM and experimental samples for the 1 L and 6 L bottles was 16.20 and 13.91%, respectively. However, the FEM was able to capture the trend of bottle deformation. The weak points of 1 L and 6 L bottles were the shoulder and the handle of the bottle, respectively. The FEM results can be applied to manage the storage time of lubricant oil with regard to stacking and to developing the design of the lubricant oil bottle as well. |
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หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Effect of Mechanical Axis on Strain Distribution after Total Knee Replacement) ผู้เขียน:Panya Aroonjarattham, Kitti Aroonjarattham, นายชาคริต สุวรรณจำรัส, อาจารย์ สื่อสิ่งพิมพ์:pdf AbstractA total knee replacement is one of the most successful orthopedic procedures to enable the patient’s return to a normal, active lifestyle. The angle of the mechanical axis depends on the surgeon’s decision, which effects the strain distribution on the femoral bone and may lead to a fracture of the femur . This study evaluated the equivalent total strain on the femoral shaft under daily activities using various models of the lower extremity with a varus knee deformity and the lower extremity with a total knee prosthesis, which was inserted at five different angles—0?, 3? valgus, 5? valgus, 3? varus and 5? varus. The results showed that the insertion of a total knee replacement in the case of a bowleg helped to reduce the equivalent total strain on the bone. The position of the prosthesis with a 3? valgus angle produced less strain distribution on the femoral bone. From the results, the mechanical axis affected the risk of the bone fracture. Considering the plastic spacer, it was found that there was an increase in the von Mises stress in the medial side of the model leg with a knee prosthesis of 3? valgus . |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Implementation and Validation of k-? Turbulence Model using C++ Open Source Code Software for Thermal Dispersion in Domestic Water Heater) ผู้เขียน:Wisuwat Matchika, นายชาคริต สุวรรณจำรัส, อาจารย์ สื่อสิ่งพิมพ์:pdf AbstractThe governing equations of the k-? turbulence model were implemented using open source computational fluid dynamic (CFD) codes and open field operation and manipulation (OpenFOAM) software to simulate the thermal dispersion between the water flow and the heater in a domestic water heater. The C++ language was used to develop the CFD codes. The QUICK (Quadratic Upstream Interpolation for Convection Kinetics) scheme was applied with the k-? turbulence model of the thermal dispersion and fluid flow. The SIMPLE (Semi-Implicit Method for Pressure-Linked Equations) algorithm was used to solve the pressure-velocity coupling under turbulence flow. The solutions of the simulations were validated using the experimental results. The transient temperatures at the outlet port of the domestic water heater were obtained using a data acquisition (DAQ) device via K-type thermocouple lines. Twelve cases of the CFD were performed in this study and produced an average error of less than 2.13% when the CFD temperatures were compared with the experimental temperatures. |