The use of hydrogen gas as a transport fuel has been investigated for a few decades, but in the recent 10 years the number of researches and pilot projects has escalated. The recent hikes in the price of oil have also added an impetus to the movement towards hydrogen and other alternatives fuels. A ...
The use of hydrogen gas as a transport fuel has been investigated for a few decades, but in the recent 10 years the number of researches and pilot projects has escalated. The recent hikes in the price of oil have also added an impetus to the movement towards hydrogen and other alternatives fuels. A methodology for the integrated production planning and reactive scheduling in the optimization of a hydrogen supply network was proposed by S. A. Heever et al. In this network's model, compressing system takes an important part of whole system. Generally, hydrogen compressor is reciprocating two-stage type, because one-stage type can not reach high pressure for charging fuel cell vehicle. A hydrogen compressing system has snubbers applied to each compressing stage. Technically, reciprocating compressor type has higher pressure increasing than the rotating one. On that character, this type is used in hydrogen handling both for storing and transferring. Special character of pressure produced by this compressor is pulsation or fluctuation. This phenomenon has a lot of disadvantages not only for the gas itself but also for equipments relating to the system. For this reasons the snubber was designed and used. In order to damp the pressure fluctuation, a flat plate is inserted inside the snubber. This plate is called as buffer. The buffer is installed crossing between inlet and outlet pipe inside of a snubber. The design of pulsation and vibration control for hydrogen compressor system should consider requirements from the API(American Petroleum Institute) Standard 618 and KS(Korean Industrial Standards) standard code. But there is no information about pulsation ratio or flow characteristic. It is explain only about structural mechanics for safety thickness due to pressure inside snubber. Therefore, this study tries to find out the optimum design using CFD analysis. In designing a snubber, several dimension such as height, diameter, buffer width and buffer angle should be defined. The methodology for designing various types of snubbers is listed in this paper. One non- dimensional number is proposed. This is the snubber height to snubber diameter ratio (H/D). In this work the snubber diameter was kept constant as 170 mm. There are three main groups of snubber type. The first group consists of model number 1 to 10. The second and the third group are model number 11 to 20 and 21 to 30 respectively. In the first, second and third group, H/D value are 3.23, 3.28 and 4.41 respectively. For the each group, the buffer angle is varied from 10 to 50 degree with 5 degree. And also without-buffer model is applied for comparison occasion. The present study shows that CFD and structure analysis can be applied to study about the snubber. The CFD analysis on the with-buffer snubber has been done and gave some information that have been summarized. The objectives of the snubber design optimization are to minimize the pressure loss and to the pressure pulsation. Numerical results such as stream line, pressure distribution and turbulent kinetic energy can be used to analyze the critical area inside the snubber and the flow behavior. Through this way, there is a specific buffer angle of the snubber has the minimum pressure loss and pulsation ratio. And also, this study represents the comparison of mechanical properties for snubber material using structural analysis and KS. Two boundary conditions are applied for structural analysis. The first one is the pressure which is applied at the inner side of the vessel, and the other one is the frictionless condition which is applied at the upper and bottom side of vessel. Main parameters of this study are adopted the temperature, thickness and pressure, and STS 304 is used as a pressure vessel material. By observing the results, the pressure vessel has larger effect of the pressure than temperature. The results of KS have the safety factor about 20~90 % higher than the results of structural analysis. And, the correlation equation is obtained from lambda and P to ensure the safety of optimum design.
The use of hydrogen gas as a transport fuel has been investigated for a few decades, but in the recent 10 years the number of researches and pilot projects has escalated. The recent hikes in the price of oil have also added an impetus to the movement towards hydrogen and other alternatives fuels. A methodology for the integrated production planning and reactive scheduling in the optimization of a hydrogen supply network was proposed by S. A. Heever et al. In this network's model, compressing system takes an important part of whole system. Generally, hydrogen compressor is reciprocating two-stage type, because one-stage type can not reach high pressure for charging fuel cell vehicle. A hydrogen compressing system has snubbers applied to each compressing stage. Technically, reciprocating compressor type has higher pressure increasing than the rotating one. On that character, this type is used in hydrogen handling both for storing and transferring. Special character of pressure produced by this compressor is pulsation or fluctuation. This phenomenon has a lot of disadvantages not only for the gas itself but also for equipments relating to the system. For this reasons the snubber was designed and used. In order to damp the pressure fluctuation, a flat plate is inserted inside the snubber. This plate is called as buffer. The buffer is installed crossing between inlet and outlet pipe inside of a snubber. The design of pulsation and vibration control for hydrogen compressor system should consider requirements from the API(American Petroleum Institute) Standard 618 and KS(Korean Industrial Standards) standard code. But there is no information about pulsation ratio or flow characteristic. It is explain only about structural mechanics for safety thickness due to pressure inside snubber. Therefore, this study tries to find out the optimum design using CFD analysis. In designing a snubber, several dimension such as height, diameter, buffer width and buffer angle should be defined. The methodology for designing various types of snubbers is listed in this paper. One non- dimensional number is proposed. This is the snubber height to snubber diameter ratio (H/D). In this work the snubber diameter was kept constant as 170 mm. There are three main groups of snubber type. The first group consists of model number 1 to 10. The second and the third group are model number 11 to 20 and 21 to 30 respectively. In the first, second and third group, H/D value are 3.23, 3.28 and 4.41 respectively. For the each group, the buffer angle is varied from 10 to 50 degree with 5 degree. And also without-buffer model is applied for comparison occasion. The present study shows that CFD and structure analysis can be applied to study about the snubber. The CFD analysis on the with-buffer snubber has been done and gave some information that have been summarized. The objectives of the snubber design optimization are to minimize the pressure loss and to the pressure pulsation. Numerical results such as stream line, pressure distribution and turbulent kinetic energy can be used to analyze the critical area inside the snubber and the flow behavior. Through this way, there is a specific buffer angle of the snubber has the minimum pressure loss and pulsation ratio. And also, this study represents the comparison of mechanical properties for snubber material using structural analysis and KS. Two boundary conditions are applied for structural analysis. The first one is the pressure which is applied at the inner side of the vessel, and the other one is the frictionless condition which is applied at the upper and bottom side of vessel. Main parameters of this study are adopted the temperature, thickness and pressure, and STS 304 is used as a pressure vessel material. By observing the results, the pressure vessel has larger effect of the pressure than temperature. The results of KS have the safety factor about 20~90 % higher than the results of structural analysis. And, the correlation equation is obtained from lambda and P to ensure the safety of optimum design.
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#정밀 기계 공업[精密機械工業]
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