• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.86-92
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• 2010

A metal diaphragm compressor has been widely used for supplying a high pressures gas. This compressor mainly consists of gas oil space and metal diaphragm. Gas sucked in the gas space is compressed by an oscillating metal diaphragm existed between the gas and oil space. A non-return discharge and suction check-valve are components of the compressor that draw off the compressed oil and gas. Those components are self-actuated by differential pressures. Therefore, the rapid response and stable operating conditions are required. In the present study, to find out the dynamic behavior of the suction, discharge valve and diaphragm compressor, the unsteady flow field has been investigated numerically by using the unsteady two-way FSI (Fluid Structure Interaction) simulation method, $k-{\omega}$ turbulent model and mesh deformation.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.769-772
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• 2009

Diaphragm compressors are used for a hydrogen compression because it can achieve high gas pressure with high purity. But diaphragm's lifetime may depend on the shape of the cavity and deflection from fluctuation the pressure change, which is necessary to monitored. In this study, the gas and hydraulic oil pressure in the cavity were measured as piston speed varies for diaphragm compressor. The results show pressure change quantities were reduced and maximum pressure points are delayed as the piston moves faster. And the hydraulic pressure were elevated as gas pressure elevated. And the compression period was more faster than expansion period.

• Transactions of the Korean hydrogen and new energy society
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• v.20 no.4
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• pp.274-282
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• 2009

Diaphragm compressor is widely used for hydrogen compression because it achieves high gas pressure without gas contamination. Diaphragm deflecting in the cavity with high pressure formed by an oil compression is the most important component in the compressor. Therefore, it is necessary to obtain deflection degree of diaphragm to predict the damage point of diaphragm. The objective of this study is to estimate the diaphragm's damage point through diaphragm deflection test by implementing with strain gauges attached on several radial points. Without gas compression, strain sum of each points varied as similarly as the variation of the pressure with respect to time. And while the motor speed was slower than 400rpm, the strain near the rim was larger than that of the center. When motor speed, however, was over 500rpm, strain became similar to that of the center and the rim. With gas compression, it was shown that the variation of the strain sum was delayed against that of the pressure and the strain near the rim was much higher than that of the center.

• Tribology and Lubricants
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• v.39 no.5
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• pp.212-215
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• 2023

Diaphragm compressors play a crucial role in safely compressing large volumes of high-purity hydrogen gas without contamination or leakage, thereby ensuring quality and reliability. Diaphragm compressors use a thin, flat, triple-layered diaphragm plate that is subjected to repetitive piston pressure for compression. They are usually made of metallic materials such as stainless steel or Inconel owing to their high-pressure resistance. However, since they are consumable components, they fail due to fatigue from repetitive pressure and vibration stress. This study aims to evaluate the scratch characteristics of diaphragms in operational environments by conducting tests on three different samples: Inconel 718, AISI 301, and Teflon-coated AISI 301. The Inconel 718 sample underwent a polishing process, the AISI 301 sample used raw material, and the Teflon coating was applied to the AISI 301 substrate at a thickness of 50 ㎛. To assess the scratch resistance, reciprocating motion friction tests were performed using a tribometer, utilizing 220 and 2000 grit sandpapers as the counter materials. The results of the friction tests suggested that the Teflon-coated sample exhibited the lowest initial friction coefficient and consistently maintained the lowest average friction coefficient (0.13 and 0.11 with 220 and 2000 grit, respectively) throughout the test. Moreover, the Teflon-coated diaphragm showed minimal wear patterns, indicating superior scratch resistance than the Inconel 718 and AISI 301 samples. These findings suggest that Teflon coatings may offer an effective solution for enhancing scratch resistance in diaphragms, thereby improving compressor performance in high-pressure hydrogen applications.

• Transactions of Materials Processing
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• v.33 no.1
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• pp.5-11
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• 2024

The development of a next-generation hydrogen compressor, a key component in the expansion of hydrogen charging infrastructure, is in progress. In order to improve compression efficiency and durability, it is important to optimize the precision forming and shearing processes of the diaphragm, which is the bellows unit cell, as well as the optimization of diaphragm shape itself. In this study, we aim to show that die and process design technology that can synchronize the inner and outer shearing points of the diaphragm for the precision forming of product can be constructed based on a numerical simulation. First, the damage model that can predict the fracture points will be determined using the shear load and shear zone measurements obtained by performing a blanking test of AISI-633 stainless steel. Next, we will explain the overall procedure based on numerical analysis model how to determine the shearing points according to the deformation pattern of urethane die for various shearing die design.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.787-790
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• 2009

There are several types of compressors which are appropriate for hydrogen gas station. Metal diaphragm type of hydrogen compressor is the one of them, a use in which satisfies the requirements of maintaining gas purity and producing high pressure over 700 bar. The objective of this study is to investigate an characteristics of compression as bulk modulus of oil varies. Three cases of bulk modulus ranging from $2{\times}10^9$, $4.52{\times}10^9$ and $7{\times}10^9$ were studied through FSI (Fluid Structure Interaction) analysis. Gas pressure, oil pressure and deflection degree of diaphragm were analysed during a certain period of compression process. Highest pressure and deflection were found in the condition of high bulk modulus of $7{\times}10^9$.

• Transactions of The Korea Fluid Power Systems Society
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• v.7 no.1
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• pp.1-5
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• 2010

This paper presents the experimental results of the radial piston type oil pump with new mechanism for a metal diaphragm hydrogen compressor. Generally, metal diaphragm type hydrogen compressor systems are operated by oil hydraulic power. In this system an oil compensating pump has been demanded to compensate for a leakage oil head chamber. The metal diaphragm type hydrogen compressor consists of an oil compensating pump, commonly used hydraulic piston pump and driven by main crank shaft. The radial piston type oil compensating pump with new rolling contacted piston mechanism is developed and experimented. The developed piston element of the radial piston pump consists of piston, steel ball, return spring, two check valves, eccentric cam and ball racer. In this study, designed 4 type pistons as and orifice hole. Operating characteristics and pressure ripple characteristics are tested under no load to 60bar loaded with every 20bar increasing step and pressure ripple and flow rate are experimentally investigated.

• Transactions of the Korean hydrogen and new energy society
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• v.20 no.6
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• pp.471-478
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• 2009

The specific some types of compressors are appropriate for a use in hydrogen gas station. Metal diaphragm type of hydrogen compressor is one of them, which can satisfy the critical requirements of maintaining gas purity and producing high pressure over 850 bar. The objective of this study is to investigate an characteristics of compression through two-way Fluid-Structure-Interaction (FSI) analysis as bulk modulus and initial volume of oil independently varies. Deflection of diaphragm, oil density, gas and oil pressure were analyzed during a certain period of compression process. According to the analysis results, bulk modulus and initial volume remarkably affected deflection of diaphragm, oil density, gas and oil pressure. The highest gas pressure were attained with the highest bulk modulus of $7e^9\;N/m^2$ and the lowest initial oil volume of 80 cc.

• Transactions of the Korean hydrogen and new energy society
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• v.20 no.2
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• pp.87-94
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• 2009

There are several types of compressors which are appropriate for hydrogen gas station. Diaphragm type of compressor is the one of them and it satisfies the requirements for that purpose in terms of maintaining gas purity and making high pressure over 700 bar. The objective of this study is to find an optimal design of oil distribution hole configuration. The number of holes is changed maintaining total cross-sectional area of holes. Five cases(1 hole, 4, 8,16 and 24 holes) were studied through Fluid Structure Interaction(FSI) analysis method. Gas and oil pressure, the deflection and stress of the diaphragm were analysed during compression and suction process respectively. There is no specific difference among the cases during compression. An additional deflection due to the existence of hole was found during suction for all case. But the highest deflection and stress were found in the 1 hole case. It was seen that 60% decrease of stress in magnitude in 24 hole case compare to the 1 hole case.

• Proceedings of the Korea Information Processing Society Conference
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• 2023.11a
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• pp.681-684
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• 2023

우리나라의 수소연료전지 차량의 점유율이 매년 증가하고 있으나, 수소충전소 설비의 잦은 중단으로 수소연료전지 차량 운전자들이 제때 차량을 충전하지 못하는 불편이 발생하고 있다. 본 논문에서는 수소충전소 설비 중 Diaphragm을 사용하는 압축기의 이상 패턴을 탐지하는 Ensemble 모델을 통해 수소충전소에서 2023년 1월 1일부터 2023년 6월 28일 동안 수집된 데이터를 분석하였으며, 해당 기간 동안 발생했던 고장에 대해 2일전부터 이상 패턴이 10,000 이상 탐지되는 결과를 얻었다.