Daejoo Machinery Co.

Dalseo, South Korea

Daejoo Machinery Co.

Dalseo, South Korea

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Chidambaram P.K.,Daejoo Machinery Co Ltd | Jo Y.M.,Andong National University | Kim H.D.,Andong National University
Journal of Thermal Science | Year: 2017

Theoretical and numerical analysis on the fluid flow and heat transfer inside a LNG evaporator is conducted in this work. Methane is used instead of LNG as the operating fluid. This is because; methane constitutes over 80% of natural gas. The analytical calculations are performed using simple mass and energy balance equations. The analytical calculations are made to assess the pressure and temperature variations in the steam tube. Multiphase numerical simulations are performed by solving the governing equations (basic flow equations of continuity, momentum and energy equations) in a portion of the evaporator domain consisting of a single steam pipe. The flow equations are solved along with equations of species transport. Multiphase modeling is incorporated using VOF method. Liquid methane is the primary phase. It vaporizes into the secondary phase gaseous methane. Steam is another secondary phase which flows through the heating coils. Turbulence is modeled by a two equation turbulence model. Both the theoretical and numerical predictions are seen to match well with each other. Further parametric studies are planned based on the current research. © 2017, Science Press, Institute of Engineering Thermophysics, CAS and Springer-Verlag Berlin Heidelberg.


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 | Year: 2011

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.


Anish S.,Daejoo Machinery Co. | Sitaram N.,Indian Institute of Technology Madras | Kim H.D.,Andong National University
Journal of Turbomachinery | Year: 2014

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.


Kumar C.P.,Daejoo Machinery Co. | Lee K.H.,Daejoo Machinery Co. | Park T.C.,Korea Aerospace Research Institute | Cha B.J.,Korea Aerospace Research Institute | Kim H.D.,Andong National University
Journal of Mechanical Science and Technology | Year: 2016

Wet compression system is typically installed in a gas turbine engine to increase the net power output and efficiency. A crucial component of the wet compression system is the nozzle which generates fine water droplets for injection into the compressor. The main objective of present work is to optimize a kind of nozzle called impact-pin spray nozzle and thereby produce better quality droplets. To achieve this, the dynamics occurring in the water jet impinging on the pin tip, the subsequent formation of water sheet, which finally breaks into water droplets, must be studied. In this manuscript, the progress on the numerical studies on impact-pin nozzle are reported. A small computational domain covering the orifice, pin tip and the region where primary atomization occurs is selected for numerical analysis. The governing equations are selected in three dimensional cartesian form and simulations are performed to predict the dynamics of water jet impinging on the pin. Systematic studies were carried out and the results leading to the choice of turbulence model and the effect of pin tip diameter are reported here. Further studies are proposed to show the future directions of the present research work. © 2016, The Korean Society of Mechanical Engineers and Springer-Verlag Berlin Heidelberg.


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 | Year: 2014

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.


Suryan A.,Andong National University | Kim D.S.,Daejoo Machinery Co. | Kim H.D.,Andong National University
Journal of Thermal Science | Year: 2010

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.


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 | Year: 2010

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.


Suryan A.,Andong National University | Kim H.D.,Andong National University | Lee J.K.,Andong National University | Kim C.K.,Daejoo Machinery Co. | Kim D.S.,Daejoo Machinery Co.
ASME-JSME-KSME 2011 Joint Fluids Engineering Conference, AJK 2011 | Year: 2011

Behavior of water droplets in air is of interest in many engineering applications. In evaporative cooling, the evaporation of liquid droplets sprayed into air streams in measured quantities cools the air. In the current study, experiments and numerical simulations are carried out to investigate the thermo-fluid dynamic behavior of water droplets of different diameters in long air ducts. Droplet size measurements at different locations were obtained with global sizing velocimetry technique. Effect of initial droplet size on temperature and relative humidity distribution of air stream in the duct is investigated. Droplet spray patterns are also analyzed to identify suitable locations for spray nozzles within the duct. Cooling effectiveness is calculated for different conditions. Experiments were conducted to validate the numerical results. Results obtained provide a clear understanding of the thermo-fluid dynamic behavior of water droplets within the duct. Copyright © 2011 by ASME.


Patent
Daejoo Machinery Co. | Date: 2012-09-19

The present invention relates to a variable throat device (100) for an air compressor, which is disposed in an air suction pipe (14) of an air compressor, and may secure reliable flow control by changing a cross-sectional area of the pipe (14) through application of force to the pipe (14), significantly reduce a possibility of unsteady flow by suppressing generation of a vortex in an air stream, secure a desired flow rate without pressure loss in the air stream, and reduce fatigue load applied to a compressor impeller through stabilization of suction flow in order to achieve significant reduction of vibration of the impeller.


Chidambaram P.K.,Daejoo Machinery Co Ltd | Song T.H.,Daejoo Machinery Co Ltd | Won Kim I.,Daejoo Machinery Co Ltd | Lee K.H.,Daejoo Machinery Co Ltd | Kim H.D.,Andong National University
Proceedings of the ASME Turbo Expo | Year: 2016

In a gas turbine engine a wet compression system is installed to increase the net power output. However, this may Erode compressor blades due to fine water droplets hitting the surface. In the present work, numerical investigations are carried out to study blade erosion by water droplets. The computational domain consists of a rotating blade jig on which four blades are mounted. This represents the simultaneous experiments being carried out. Sliding mesh method is used to incorporate rotary movement of the blades. Water is injected as spray using an impact-pin nozzle. Experimentally measured spray parameters like the flow rate, particle diameter, etc. are given as initial and boundary conditions in the simulations. Discrete Phase Model (DPM) is used to track the particles in the domain. Droplet parameters like average velocity, diameter and number of droplets hitting each cell on the blade surface are monitored. These parameters are then used to predict the rate of erosion on the surface. In this manuscript, the progresses in the prediction of blade erosion at various blade rotational speed (rpm) is reported. Copyright © 2016 by ASME

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