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Dalseo, South Korea

Kang H.S.,Sungkyunkwan University | Oh J.,Daejoo Machinery Co. | Han J.S.,Andong National University
Transactions of the Korean Society of Mechanical Engineers, B

This paper discusses a one-way fluid structural interaction (FSI) analysis and shape optimization of the impeller blades for a 15,000 HP centrifugal compressor using the response surface method (RSM). Because both the aerodynamic performance and the structural safety of the impeller are affected by the shape of its blades, shape optimization is necessary using the FSI analysis, which includes a structural analysis for the induced fluid pressure and centrifugal force. The FSI analysis is performed in ANSYS Workbench: ANSYS CFX is used for the flow field and ANSYS Mechanical is used for the structural field. The response surfaces for the FSI results (efficiency, pressure ratio, maximum stress, etc.) generated based on the design of experiments (DOE) are used to find an optimal shape for the impeller blades, which provides the maximum aerodynamic performance subject to the structural safety constraints. © 2014 The Korean Society of Mechanical Engineers. Source

Anish S.,Daejoo Machinery Co. | Sitaram N.,Indian Institute of Technology Madras | Kim H.D.,Andong National University
Journal of Turbomachinery

Interaction between rotating impeller and stationary diffuser in a centrifugal compressor is of practical importance in evaluating system performance. The present study aims at investigating how the interaction influences the unsteady diffuser performance and understanding the physical phenomena in the centrifugal compressor. A computational fluid dynamics (CFD) method has been applied to predict the flow field in the compressor, which has a conventional vaned diffuser (VD) and a low solidity vaned diffuser (LSVD). The radial gaps between impeller and diffuser and different flow coefficients are varied. The results obtained show that the major parameter that influences the unsteady variation of diffuser performance is due to the circumferential variation of the flow angle at the diffuser vane leading edge. The physical phenomena behind the pressure recovery variation are identified as the unsteady vortex shedding and the associated energy losses. The vortex core region as well as the shedding of vortices from the diffuser vane are triggered by the variation in the diffuser vane loading, which in turn is influenced by the circumferential variation of the impeller wake region. There is little unsteady variation of flow angle in the span-wise direction. This indicates that the steady state performance characteristics are related to the span-wise variation of flow angle, while the unsteady characteristics are contributed by the circumferential variation of flow angle. At design conditions, dominant frequency components of pressure fluctuation are all periodic and at near stall, these are aperiodic. © 2014 by ASME. Source

Suryan A.,Andong National University | Kim D.S.,Daejoo Machinery Co. | Kim H.D.,Andong National University
Journal of Thermal Science

Large-capacity compressors in industrial plants and the compressors in gas turbine engines consume a considerable amount of power. The compression work is a strong function of the ambient air temperature. This increase in compression work presents a significant problem to utilities, generators and power producers when electric demands are high during the hot months. In many petrochemical process industries and gas turbine engines, the increase in compression work curtails plant output, demanding more electric power to drive the system. One way to counter this problem is to directly cool the inlet air. Inlet fogging is a popular means of cooling the inlet air to air compressors. In the present study, experiments have been performed to investigate the suitability of two-fluid nozzle for inlet fogging. Compressed air is used as the driving working gas for two-fluid nozzle and water at ambient conditions is dragged into the high-speed air jet, thus enabling the entrained water to be atomized in a very short distance from the exit of the two-fluid nozzle. The air supply pressure is varied between 2.0 and 5.0 bar and the water flow rate entrained is measured. The flow visualization and temperature and relative humidity measurements are carried out to specify the fogging characteristics of the two-fluid nozzle. © 2010 Science Press and Institute of Engineering Thermophysics, CAS and Springer-Verlag Berlin Heidelberg. Source

Suryan A.,Andong National University | Yoon Y.K.,Daejoo Machinery Co. | Kim D.S.,Daejoo Machinery Co. | Kim H.D.,Andong National University
Evolutionary Ecology

Increasing power demands have necessitated the development of energy efficient systems in the industrial sector. At present, about 10% of the overall electric power used by large industrial plants is consumed by high-capacity compressors supplying compressed air. Likewise, in a gas turbine power plant, nearly half the generated power is used for driving the compressor. The work of compression is proportional to inlet air temperature, and cooling the inlet air can save considerable amount of power in large turbo machines during hot summer months. Inlet fogging is a popular means of inlet air cooling, and fog nozzles are the most critical components in an inlet fogging installation. Majority of these installations employ impaction pin nozzles. In the present work, experiments are conducted over a wide range of operating parameters in variable length wind tunnels of different cross sections in order to investigate the performance of impaction pin nozzle in inlet fogging. Flow visualization and measurements are carried out to analyze the fog behavior and identify suitable nozzle locations in typical air ducts. The results show that impaction pin nozzles are suitable for inlet fogging applications. © 2011 The Korean Society of Mechanical Engineers and Springer-Verlag Berlin Heidelberg. Source

Suryan A.,Andong National University | Lee J.K.,Andong National University | Kim D.S.,Daejoo Machinery Co. | Kim H.D.,Andong National University
Journal of Thermal Science

Evaporative cooling is a widely used air cooling technique. In this method, evaporation of a liquid in the surrounding air cools the air in contact with it. In the current investigation, numerical simulations are carried out to visualize the evaporation and dynamics of tiny water droplets of different diameters in a long air duct. The effect of initial droplet size on the temperature and relative humidity distribution of the air stream in the duct is investigated. Three different initial conditions of air are considered to verify the influence of ambient conditions. Droplet spray patterns are also analyzed to identify the suitable locations for the spray nozzles within the duct. The results obtained are displayed in a series of plots to provide a clear understanding of the evaporative cooling process as well as the droplet dynamics within the ducts. © 2010 CAS and Springer-Verlag Berlin Heidelberg. Source

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