• Journal of the Korean Institute of Gas
• /
• v.19 no.1
• /
• pp.18-22
• /
• 2015

This paper presents the stress strength safety of LPG steel cylinder for various corner radiuses of upper round end plate and lower round end plate by using a finite element method. The FEM analyzed results indicate that the most influential elements is a corner radius of upper round end plate and lower round end plate rather than a thickness of LPG cylinder. But, the thickness of a steel cylinder is an important design element considering for a weight reduction of a cylinder. Thus, this paper recommends that the LPG steel cylinder thickness is 2.3~2.6mm and the corner radius of upper round end plate and lower round end plate is over 157mm as an optimum design for the maximum testing pressure of 3.04MPa.

• Journal of the Korean Chemical Society
• /
• v.46 no.4
• /
• pp.317-323
• /
• 2002

The composition of trace materials in domestic circulated LPG are determined. The sampling points are two cylinders of LPG cylinder re-inspection center, six vaporizer of LPG-supplying group facilities, and the compressed oil from one LPG station. In the trace materials from cylinder of LPG cylinder-reinspection center, alkene and diene derivative (No. of carbon ${\leq}9),$ aromatic compounds, and tarry chemicals(No. of carbon ${\geq}10)$ are 1.5~39.9%, 0.7%, 57.8~96.0%, respectively. While in the trace materials from LPG-supplying group facilities and in the oil from LPG station, tarry chemicals(No. of carbon>10) exceed 96.6%. Nine samples are classified into three clusters. One cluster is the sample of SE company cylinder-reinspection center(Euclidian distance between S company LPG cylinder-reinspection center and SE company cylinder-reinspection center=2.11), the other is the sample of SE company LPG cylinder-reinspection center(Euclidian distance between from samples of LPG-supplying group facilities including compressed oil from LPG station=0.110) the third is the samples of LPG-supplying group facilities(Euclidian distances among them<0.075). The compositions of samples from LPG-supplying group facilities are similar to those of oil from LPG station. Furthermore densities of samples from LPG-supplying group facilities and compressed oil in LPG station are 0.873, 0.873 [0.00798 (99% confidence limits) respectively. It was presumed that tarry chemicals had been leached from the compressed oil of LPG supplying facilities.

• Journal of the Korean Institute of Gas
• /
• v.11 no.2 s.35
• /
• pp.55-59
• /
• 2007

This paper presents the strength safety of a LPG cylinder, which is fabricated by a steel sheet forming and a welding technology. The strength safety of a cylinder is guaranteed by analyzing a stress distribution of a LPG cylinder structure using a finite element method. The FEM computed results indicate that the hydraulic test gas pressure of $31kg/cm^2$ generates a concentrated local stress near the upper round end plate, which exceeds the yield strength of a LPG cylinder. Thus, the current hydraulic test pressure may be rechecked and revised because this pressure increases the fatigue failure and decreases the lift of the pressure vessel. The normal operation and sealing gas pressures such as $9kg/cm^2\;and\;18.6kg/cm^2$ are relatively safe for a steel LPG cylinder.

• Journal of Energy Engineering
• /
• v.11 no.2
• /
• pp.160-165
• /
• 2002

The heavy-duty LPG-fueled single cylinder engine was designed and developed as a fundamental equipment for analyzing combustion processes and emission performances. The cylinder head and the piston crown were modified to fire the LPG in the engine. The flywheel was also fabricated to minimize the vibration of the single cylinder engine. The size of bore and stroke of the tested engine are 130 mm and 140 mm, respectively. Compression ratios were varied 8 to 9 with different piston crown shapes. The developed single cylinder engine operates at 1,000 rpm for this work. The major conclusions of this work are; (1) the power of the developed engine was peaked at the condition of equivalence ratio 1.0 at three different compression ratios; (2) the power is slightly increased with the increase of compression ratio; (3) the optimum ignition timing is retarded with the increase of compression ratio ranged 2 to 10 crank angle.

• Journal of Advanced Marine Engineering and Technology
• /
• v.31 no.1
• /
• pp.26-33
• /
• 2007

The intake swirl motion, as one of dominant effects for an engine combustion. is very effective for turbulence enhancement during the compression process in the cylinder of 2-valve engine. Because the combustion flame speed is determined by the turbulence that is mainly generated from the mean flow of the charge air motion in intake port system. This paper describes the experimental results of swirl flow and combustion characteristics by using the oil spot method and back-scattering Laser Doppler velocimeter (LDV) in 2-valve single cylinder transparent LPG engine using the liquid phase LPG injection. For this. various intake port configurations were developed by using the flow box system and swirl ratios for different intake port configurations were determined by impulse swirl meter in a steady flow rig test. And the effects of intake swirl ratio on combustion characteristics in an LPG engine were analyzed with some analysis parameters that is swirl ratio. mean flow coefficient, swirl mean velocity fuel conversion efficiency. combustion duration and cyclic variations of indicated mean effective pressure(IMEP). As these research results, we found that the intake port configuration with swirl ratio of 2.0 that has a reasonable lean combustion stability is very suitable to an $11{\ell}$ heavy-duty LPG engine with liquid phase fuel injection system. It also has a better mean flow coefficient of 0.34 to develope a stable flame kernel and to produce high performance. This research expects to clarify major factor that effects on the design of intake port efficiently with the optimized swirl ratio for the heavy duty LPG engine.

• Journal of the Korean Institute of Gas
• /
• v.22 no.2
• /
• pp.72-77
• /
• 2018

This paper presents the FEM analysis results on the strength safety of LPG fuelling nozzle, which is composed of ball valve and long cylinder tube. For the strength safety analysis of LPG fuelling Nozzle, the gas pressure of 0.5~3.5MPa has been supplied to the ball valve and long cylinder tube bodies with the wall thickness of 1.7~3.5mm. The maximum von Mises stress of the ball valve with 1.7mm wall thickness is 25.4MPa for the supply gas pressure of 3.5MPa, which is 25.9% compared with that of the yield stress of the brass. And the maximum von Mises stress was 23.7MPa when a 3.5MPa gas pressure was applied to a long cylinder tube with a wall thickness of 1.7mm, which was 6.7% more safe than the ball valve which was analyzed under the same conditions. For the increased wall thickness, 2.0mm of the long cylinder tube, the maximum von Mises stress of 20.2MPa is 14.8% more safe compared with that of 1.7mm wall thickness of the same cylinder tube. Thus, the wall thickness of the ball valve and cylinder tube is recommended as an optimized thickness of 1.7~2.0mm for the strength safety of the LPG fuelling nozzle.

• Journal of the Korean Institute of Gas
• /
• v.11 no.2 s.35
• /
• pp.37-42
• /
• 2007

This paper presents the leakage safety of two O-rings, which are located at the rectangular groove between a valve body and a valve stem. The leakage safety analysis of 0-ring seals has been computed as functions of a compression set and a liquefied petroleum gas pressure of a LPG cylinder using a FEM program, MARC. The FEM computed results indicate that the loads from the filling pressure of $8kg/cm^2$ to the upper limit of the safety valve, $24.8kg/cm^2$ work safely according to the pressure vessel code. But two O-rings should consider the aging effects for an increased safety of the o-ring.

• Journal of the Korean Institute of Gas
• /
• v.11 no.1 s.34
• /
• pp.34-39
• /
• 2007

In this paper, the FEM result has been presented for a sealing safety between a valve packing and a valve seat during a open and close operation in a LPG cylinder. The sealing operation of a LPG valve is completed when the valve packing in which is made by a nylon-66 polymer is to stop a LP gas flow, which flows out from the outlet of a brass pipe in a LPG cylinder. The contact sealing mechanism of the valve may be classified by a flat contact of an unused valve packing and a circular groove contact of an used valve packing in a current LPG valve. Based on the FEM and experimental investigations the sealing force, 4.9 MPa for a flat contact mode of the unused valve packing is a little high compared to that of the used valve packing, which shows a circular groove contact geometry against a valve seat. But these sealing pressures for two contact modes are very low compared to the ultimate strenath 83 MPa of the nylon-66 and this may be designed with a excess strength of the valve.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.28 no.10
• /
• pp.1178-1183
• /
• 2004

The purpose of this study was to investigate the influence of compression ratio on engine performance in a LPG(Liquefied Petroleum Gas) engine converted from a diesel engine. In ordor to determine the ideal compression ratio, a variable compression ratio 4-cylinder engine was developed. Retrofitting a diesel engine into a LPG engine is technically very complicated compared to a gasoline to LPG conversion. The cylinder head and the piston crown were modified to bum LPG in the engine. Compression ratios were increased from 8 to 10 in an increment of 0.5, the ignition timing was controlled to be at MBT(Minimum Spark Advance for Best Torque) for each case.

• Journal of the Korea Safety Management & Science
• /
• v.16 no.4
• /
• pp.175-183
• /
• 2014

This study examined the effective system, which manages LPG Gas Cylinder by inserting an electronic tag or module to store a production year, material specification, charging data, management data, and warehousing data. Therefore, the user can effectively monitor the checking date, reexamining the gas cylinder (or not), and manufacture and expiration date. Moreover, through this study, the user can simply monitor a production date, warehousing data, and charging frequency by connecting a mobile app and a gas cylinder in which has an electronic tag or module at any time.