TOTAL STATION EQUIPPEDWITH A BUILT-IN CRACK SCALE

This paper describes KUMONOS, which is a total station equipped with a built-in crack scale. Using this system enables one to accurately measure the width of cracks in structures from a distance. When compared to the traditional inspections based on hand-sketches, the advantages of the inspections using KUMONOS are high precision, safety and economic performance. Therefore, KUMONOS can be expected to perform a constructive role in maintaining structures

オレフィンオキシドノジュウゴウニカンスルケンキュウ

京都大学0048新制・論文博士工学博士乙第1593号論工博第340号新制||工||153(附属図書館)2437UT51-45-L265(主査)教授 古川 淳二, 教授 三枝 武夫, 教授 熊田 誠学位規則第5条第2項該当Kyoto UniversityDA

New Concept of On-Line Wash for Centrifugal Compressor

Case StudiesThis paper introduces the development of new concept of on-line wash oil injection system which includes the optimization of quantity of washing oil, location of injection nozzles, direction of nozzle entry, hole size as well as control system. The process gas compressor is the most critical unit in an ethylene plant and several types of contaminates can often foul the compressor flow path, causing deterioration in performance and significant losses in plant production. In order to prevent the efficiency losses due to fouling during long term operation, wash oil is injected as regular intervals/ continuously in process gas compressors. As common practice, wash oil injection nozzle are usually installed on the suction piping as well as return bend on each stage. Foulant material has been reported during turn around (and with few years of operation) even though wash oil injection has been carried out at required intervals. User and OEM investigated the root cause of this phenomenon and constructed the new concept design of on-line wash oil injection system in consideration of wash area, oil quantity, erosion and feasibility of machine construction etc. by means of FEM (Finite Element Method) analysis as well as CFD (Computational fluid dynamics). To verify the effectiveness of this new concept of oil injection system, component test and actual machine verification test was conducted and successfully completed under User’s witness. After completion of the test, OEM delivered newly developed oil injection system in user site that the fouling materials on the compressors were reported with conventional oil injection system, and commercial operation was started. User and OEM confirmed the effectiveness of newly developed system at site process gas compressor by checking the compressor performance

Impeller Stall Induced by Reverse Propagation of Non-Uniform Flow

LecturesIn the case of centrifugal compressors, minor non-uniform flow upstream of the impeller is induced by an asymmetrical configuration in the circumferential direction at the compressor suction casing. This non-uniform flow is transmitted to the impeller discharge, but this minor non-uniform flow does not usually cause an adverse effect on the impeller stage performance. However, we found this is amplified at the return channel due to flow separation at reduced flows (depending on return channel geometry), and the amplified non-uniform flow did induce impeller stall by reverse propagation from the return channel to the impeller. These non-uniform flows caused a significant operating range reduction for a large flow coefficient impeller. The aerodynamics issues were mitigated using CFD analysis techniques, and eventually confirmed by the compressor performance during shop performance testing. The OEM conducted the CFD analyses using two (2) return channel geometries with several CFD models to verify the effect of the return channel geometry on impeller stall and to Copyright© 2018 by Turbomachinery Laboratory, Texas A&M Engineering Experiment Station confirm the most suitable CFD modeling method for stall evaluation. Shop performance tests utilizing both return channel geometries were conducted and compared to the CFD analyses. These studies were conducted while collaborating with the end-user. The steady CFD calculation was conducted with frozen rotor interface between full annulus impeller and stator parts. The modeling of diffuser and return channel was varied as follows: (1) 1-pitch model for the return channel with mixing plane at diffuser (2) Full-annulus model for the return channel with a mixing plane at the diffuser (3) Full-annulus model for the return channel without a mixing plane at the diffuser From the above studies and the shop performance testing, it was confirmed that the proposed CFD modeling method could simulate the measurements taken during the shop performance tests and that the CFD modeling met

Development of High-Pressure Ratio and Wide-Operation Range 700bar Compressor

LecturePre-Salt development projects continue to expand offshore Brazil into ever deeper waters year after year. Consequently, the required Discharge Pressures for Re-Injection Compressors aboard FPSO’s are likely to exceed current 550 bar levels, and requirements for design of higher pressure compressors becomes more severe. This paper presents development of super high pressure compressor and the results of verification tests. Super high pressure compressor can be used as re-injection compressor or injection compressor such as in the CCS plant and FPSO. Rotor stability is the most considerable requirement for super high pressure operation because of the high density flow destabilization force in the compressor. From the point of view of rotor dynamics, the short bearing span and high shaft diameter are desirable for the stability of the rotor. On the other hand, from the point of view of aerodynamics performance, that rotor arrangement may decrease the performance. Some parametric study was conducted to optimize the boss ratio of compressor stage to get both high rotor dynamic stability and high aerodynamic performance. Rotating stall can be the cause of sub-synchronous vibrations in super high pressure operation condition and it induces narrow operation range. To prevent such situation, vaned diffuser was applied for developed compressor stage and it can also help to reduce the diffuser radius space. Seal leakage flow have large effects on the rotor stability and aerodynamic performance. For this item, the hybrid construction of hole pattern seal and step labyrinth seal was proposed. Hole pattern seal is well known as damping seal for high pressure compressor. CFD dynamic analysis and dynamic characteristics test for this hybrid hole pattern seal are introduced under the condition of high density by using hydraulic shaker device. The extensive verification test of developed super high pressure compressor were conducted with impeller of optimized boss ratio, vaned diffuser and hybrid honeycomb seal, and has demonstrated the robustness for all field operation condition including Molecular weight variation with high aerodynamic performance and small vibration

Investigation Results for Surge Phenomena of Centrifugal Compressor Related with Piping Arrangements and Test Conditions

LectureThe shop performance test of a hydrogen recycle gas compressor for refinery plant was conducted with the suction pressure of 50barA based on ASME PTC-10 Type-2 test. During testing, a surge phenomenon was observed at a flow rate 15 % higher than the predicted surge flow. From the FFT results of the shaft vibration and the pressure pulsation at the discharge of the compressor, the peaks of sub-synchronous components were observed at two frequencies of 2Hz and 30Hz near surge flow. The sub-synchronous vibration at 30Hz was considered to be caused by rotating stall, but the 2Hz was too low to be attributable to rotating stall. As an assumption of the root cause, the acoustic characteristics of shop test loop were checked. The calculated and measured Helmholtz resonance frequency of the shop test loop was in agreement with the sub-synchronous frequency of 2Hz. For further investigation, additional tests were carried out with a fully instrumented test loop. Many different test cases were carried out by changing the suction pressure and piping size, with and without installing a perforated plate near the compressor. The originating flow points of the surge were different in each case. The originating flow point of the surge was small when the suction pressure was high and/or the perforated plate was installed. From the investigation results, it was found that the mode of the acoustic characteristics of test loop was related with the originating flow point of surge. In case the compressor discharge is the node of pressure pulsation, it becomes the anti-node of flow fluctuation. In this case, if the flow approaches surge, the flow fluctuation at the compressor discharge is increased. It transmits to the compressor suction, and it would cause the surge of the compressor. In case the perforated plate was installed near the compressor discharge, the pressure pulsation at the compressor discharge was increased. It decreased the flow fluctuation of the compressor discharge, and the surge became suppressed

Modeling for the Optimal Co-scheduling Problem of Data Replication and Job Execution in Data Grids

There are many challenges in Data Grids, and especially the data replication and the job scheduling are significant problems. There have been many works on the data replication and the job scheduling in Data Grids separately. However, there are still only a few works on solving those two significant problems together in Data Grids. In this work, we propose the optimization model for the co-scheduling problem of the data replication and the job execution in Data Grids, which is more realistic and widely adaptable to real systems. We use 0-1 integer programming model to formulate the co-scheduling problem of the data replication and the job scheduling. Our final goal in this work is to find the optimal solution, that is, the data replication and job assignment, such that it minimizes the response time. The proposed optimization model will lead us this goal