• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.297-298
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• 2013

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.1297-1298
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• 2013

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.4
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• pp.47-56
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• 2005

In GPS/INS/barometer navigation system for UAV, vertical channel damping loop was introduced to suppress divergence of the vertical axis error of INS, which could be reduced to the level of accuracy of pressure altitude measured by a pitot-static tube. Because static pressure measured by the pitot-static tube depends on the speed and attitude of the vehicle, static pressure error models, based on aerodynamic data from wind tunnel test, CFD analysis, and flight test, were applied to reduce the error of pressure altitude. Through flight tests and sensitivity analyses, the error model using the ratio of differential pressure and static pressure turned out to be superior to the model using only differential pressure, especially in case of high altitude flight. Both models were proposed to compensate the effect of vehicle speed change and used differential and static pressure which could be obtained directly from the output of pressure transducer.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.1149-1149
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• 2006

The leakage characteristic is an important factor in power plant. However, most of power plant have efficiency problem which is occurred leaking between high pressure steam turbine axle and stator. The labyrinth seal which is used between the main turbine axle and stator in the power plant. Because it is able to be non-contact seal and it is minimize clearance to decrease the leakage. But its actual system is too huge to experiment. Therefore, most steam turbine seal performance tests were conducted by air similarity test. This paper described a test facility and program for air similarity test of high pressure steam turbine seal. A test facility has been designed and built to evaluate leakage verification of labyrinth seal. The test facility consist of air compressor, anti-swirl labyrinth seal for 1/3 air similarity model, pressure transducer, air flow measure system, instrumentation and auxiliary system. For evaluation of steam turbine seal performance, the air similarity test of labyrinth seal leakage verification was conducted and we compared experiment data and analysis result.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.395-400
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• 2017

Hydraulic test was conducted to evaluate the structural strength of valve exposed to high pressure environment during combustion progress. For the proof pressure, 1.05 times higher pressure than MEOP was applied in the hydraulic test. Two units of valves were used in the hydraulic test. The result for measured strain of the valve dependent on the pressurization conditions during the test were verified comparing with the results for the finite element analysis. Observing the difference between the results for the finite element analysis and the hydraulic test, the difference was within 20% error and the plastic deformation was not generated.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.4
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• pp.68-75
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• 2018

This study presents the performance test results and the analyses of the vitiated air heater with high temperature and high pressure. In the performance test, four test conditions and three rake measurement conditions were implemented. In the results of the performance test, the vitiated air heater met targets of temperature and flow rate, and the performance with maximum temperature of 2000 K and maximum combustion pressure of 40 bar was confirmed. Flow rate of provided methane increased 36% more than what was calculated, and 19.6% difference was displayed between measured temperature and theoretically calculated temperature.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.4
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• pp.546-551
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• 2020

Generally, surface vessels have many compartments for operation and living quarters, and each compartment is an important space for the ship's survivability. During ship construction, a compartment leak test is necessary and is carried out on each vessel. However, the current test method is in doubt when looking at the actual test results. The reason is that only one pressure gauge is used for the measurement to check the air, so an uncomprehended phenomenon is detected during group compartment leak tests. From this point of view, an improved test device and method are needed. In this study, a multi-channel data acquisition device with multiple pressure sensors is proposed to detect each compartment's pressure variation or pressure drop. This test is a more confidential compartment leak test than the current method, and the test device can show real-time pressure detection values of each of the pressure sensors, which are installed in each compartment, including unmanned space.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.9
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• pp.120-127
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• 2020

This study examined the operation of a pressure gauge for measuring the internal pressure of a barrel. During the ammunition performance evaluation test, the internal pressure of the barrel was measured mainly using a copper crusher gauge. The internal piezo gauge (IPG) was used to replace the pressure measurement method, and the test results were analyzed to verify the operability of the IPG. For verification, actual shooting test data were used, and a t-test was used to analyze the results. The 155MM KH179 and M119 series propellant were used for the test equipment and ammunition. The results confirmed that there was no difference between the mean values of the two data results at a significance level of 5% for the data values between the copper gauge and the IPG. The use of the IPG was verified by replacing the existing copper gauge to measure the internal pressure of the barrel, and it was confirmed that the application width could be widened in terms of diversity of test measurement methods. Based on the results of this test, it can be applied to the compression measurement test of various types of ammunition in addition to the propellant charges.

• Journal of the Korean GEO-environmental Society
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• v.15 no.5
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• pp.67-74
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• 2014

In this study, a constant rate of strain test (CRS) and oedometer test was performed in order to study the consolidation characteristics to the liquid limit using a re-shaped clay which was preconsolidated at a constant pressure. Consolidation samples were made of kaolinite which was mixed with bentonite of 6 %, 9 %, 12 % and 15 % of it by weight and the test value of liquid limit of samples were appeared in 77 %, 84 %, 88 % and 91 % respectively. And then consolidation samples which were agitated sufficiently adding distilled water 2 times of liquid limit were preconsolidated in the condition of a constant pressure of 0.2 MPa. The oedometer test which is commonly used recently and the consolidation test of constant rate of strain which were applied in 0.001 %/min, 0.004 %/min, 0.01 %/min rate of strain according to ASTM, D4186-82 were performed and the preconsolidation pressures were compared and analyzed at 0.2 MPa preconsolidated pressure. As a result, in the case of low value of liquid limit, preconsolidation pressure was appeared same as 0.2 MPa preconsolidated pressure at the high speed strain rate, and in the case of high value of liquid limit, preconsolidation pressure was appeared same as 0.2 MPa preconsolidated pressure at the low speed strain rate.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.766-773
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• 2021

Chemicals, such as ammunition, are disposable items that cannot be reused because of their operational characteristics. The reliability of the test process and test results are important factors in evaluating the performance of guns and ammunition. The pressure after firing is a crucial value in an acceptance test of guns and ammunition performance; hence, accurate measurements are required. The pressure in the artillery is measured using the copper crusher gauge. The compression amount of copper is converted into a pressure by either a length-pressure conversion table or conversion formula. Therefore, the exact measurement of the squeeze of the copper crusher is related directly to the correct estimate of the pressure. Currently, the pressure is measured manually by the operator, which always includes some human error. In this study, the cause of the measurement error was analyzed, and the automatic measuring system for copper crusher deformation was developed to minimize the error elements. A copper crusher could be measured using the probe sensor and CCD camera, and the Jig for stable positioning was also designed. A designated SW was also developed for the system operating and measurement-analysis. This measuring system through this study may be used for an ammunition stockpile reliability test and gun/ammunition acceptance test.