• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.11a
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• pp.315-318
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• 2007

A dynamic simulation of a turbo-shaft engine was performed for analysis of transient-state and engine-starting characteristics using the MATLAB/SIMULINKTM. The turbo-shaft engine was modelled based on thermodynamic and rotor dynamic relations. The analysis of engine starting characteristics was performed by monitoring the rate of the pressure, temperature and mechanical torque changes along the engine stations by the torque input generated from the accessary power unit and transmitted to the power turbine. The simulation of the transient-state characteristics of the engine was performed under fuel flow rate increase from the steady-state condition. For the future study, engine control unit will be added to the basic turbo-shaft engine model to enhance capability of engine performance simulation.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.239-248
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• 2010

This paper dealt with the Performance Modeling of a low-bypass turbofan engine for supersonic aircraft. The Pratt and Whitney F100-PW-229 engine has been employed for low-bypass turbofan engine performance modeling. Generally, The complete commercially-classified information concerning the engine are unknown. So, Components' generic characteristics are described and assumptions made in order to model the F100-PW-229 engine performance model. All the analysis has been undertaken using published data taken from the open literature. The results of the Engine Performance using Gasturb11 showed that the Engine performance model was evaluated to be properly constructed.

• Journal of Advanced Marine Engineering and Technology
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• v.25 no.6
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• pp.1260-1271
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• 2001

The simulation program which predicts the gas behavior in a spark ignition engine has been developed and verified by the comparison with the experimental results foy the MPI engine, naturally aspirated and turbochared engines with a carburettor. First paper describes the calculations of the behavior of gas in the intake and exhaust system. The generalized method of characteristics including friction, heat transfer, area change and entropy gradients was used to analyse the pipe flow The constant-Pressure model was applied for the analysis of the flow through engine valved, and the constant-pressure perfect-mixing model was applied for the flow at manifold junction. The concept of the sudden area change was used for the muffler and catalytic convertor. Fer the plenum chamber in an MPI engine, constant-pressure model and constant-volume model were both examined. Through the comparison of predicted results with experiments, the simulation program was verified by showing good prediction of the behavior of IC engine qualitatively and quantitatively under wide range of operating conditions.

• 한국연소학회:학술대회논문집
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• 2002.11a
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• pp.215-222
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• 2002

It has been well acknowledged that intake system plays great role in the performance of reciprocating engine. Well-designed intake system is expected to not only increase engine efficiency but also decrease engine emission, which is one of the most urgent issues in the automotive society. Thorough understanding of the flow in intake system helps great to design adequate intake system. Even though both experimental and numerical methods are used to study intake flow, numerical analysis is more widely used due to its merits in time and economy. Intake system of In-line 6-Cylinder CNG engine was chosen for the analysis ICEM CFD HEXA was used to create 3-D structured grid and FIRE code was used for the flow analysis in the intake system. Due to the complexity of the geometry standard ${\kappa}-{\varepsilon}$ turbulence model was applied. Numerical analysis was performed for various inlet and outlet boundary conditions under both steady and transient flow. Inlet mass flow rate and outlet pressure variation were changing parameters with respect to engine speed. Flow parameters, such as velocity, pressure and flow distribution, were evaluated to provide adequate data of this intake system.

• Journal of Aerospace System Engineering
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• v.3 no.2
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• pp.20-23
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• 2009

The structural analysis of liquid rocket engine was performed in the case of sinusoidal vibration load to verify structural safety. The finite element model is composed with main liquid rocket engine components, combustion chamber, turbopump, gas-generator, pyro-starter, main pipes, main valve, heat-exchanger, gimbal-mount and brackets. Natural vibration mode analysis and structural analysis for sinusoidal vibration load were performed. The natural mode frequency of liquid rocket engine is twice than that of launch vehicle. In the case of stress result of sinusoidal vibration load, the part of maximum stress has 1.4 margin, so the engine structure is safe for sinusoidal vibration load.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.251-255
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• 2012

Structural intensity has been mainly utilized to identify vibration energy flow in a vessel. In this paper, the structural intensity of a shuttle tanker subjected to H-moment of the main engine was calculated using a finite element model. From the analysis, it was found that the top-bracing elements, which support the main engine onto the hull structure to prevent the excessive transverse vibration of the main engine, play the role of the dominant path and sink for vibration energy flow from the main engine. Therefore, the structural intensity was controlled by the modification of stiffness and damping characteristics of the top-bracing elements. As a result, it is observed that the transverse vibration level at the center of navigation bridge deck decreased after the control of structural intensity.

• Journal of Advanced Marine Engineering and Technology
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• v.22 no.4
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• pp.560-568
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• 1998

Recently to develop an automobile with better properities many researches and investments have been executed. In this paper we intend to improve the automobile properties by reducing the weight of the engine without changing the dynamic characteristics. At first the vibration analysis by the Substructure Synthesis Mehtod and the exciting test of the engine model performed to confirm the reliability of the analyzing tools. And the weight minimiza-tion is performed by the Sensitivity Analysis and the Optimum Structural Modificationl. To decrease the engine weight ideally the weight of the parts with the low sensitivity is to cut mainly and the changing quantity of the natural frequency by the cut is to be recovered by the weight modification of the parts with the high sensitivity. As actually the mathematical unique solution for the homogeneous problem(i. e. 0 object func-tion problem)does not exist we redesign the engine block with much thinner initial thickness and recover the natural frequencies and natural modes of original structure by the sensitivity analy-sis and then observe the Frequency Response Function(FRF) for the interesting points. In this analysis the original thickness of the engine model is 8mm and the redesigned initial thicknesses are 5mm and 6mm, And the number of the interesting natural frequencies are 1, 2, 3, 4 and 5 respectively.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.10a
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• pp.326-332
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• 1997

Recently to develop an automobile with better prosperities, many researches and investments have been executed. In this paper we intend to improve the automobile properties by reducing the weights of the engine without changing the dynamic characteristics. At first we perform the vibration analysis by the Substructure Synthesis Method and execute the exciting test for the engine model, and observe the coincidences of two results to confirm the reliability of the analyzing tools used. The weight minimization is performed by the Sensitivities of the Natural frequencies of the engine block. To decrease the engine weight ideally, the parts of the sensitivity zero are to be cut mainly, and the changing quantity of natural frequency by the cut is to be recovered by the structural modification for the parts with the good sensitivity. But, as actually the mathematical solution for the homogeneous problem(i.e. 0 object function) do not exist, we hereby redesign the block with much thinner thickness and recover the natural frequencies and natural modes to original structure's by the sensitivity analysis. And the Frequency Response Functions(FRF) are to be observed for the interesting points. In this analysis, the original thickness of the engine model has 8 mm of thickness, and the thickness redesigned is 5 mm and 6 mm. And we are to try to recover the 1, 2, 4, and 5 lower natural frequencies interested.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.5
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• pp.9-16
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• 2006

The present study is to simulate coolant flow in IC engine cooling passages under subcooled nucleate boiling conditions and investigate thermal stress analysis of the solid part. To consider nucleate boiling heat transfer effect, Chen's empirical formula is used through user subroutine programing in CFD code and then nucleate boiling model is compared with Robinson's experimental results, which shows reasonable agreement. This Chen's nucleate boiling model is applied to single cylinder IC engine model and we do cylinder liner thermal stress analysis using commercial FEM code.

• Journal of Mechanical Science and Technology
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• v.15 no.8
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• pp.1196-1204
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• 2001

The effects of EGR(Exhaust Gas Recirculation) on heavy-duty diesel engine performance, NO and soot emissions were numerically investigated using the modified KIVA-3V code. For the fuel spray, the atomization model based on the linear stability analysis and spray wall impingement model were developed for the KIVA-3V code. The Zeldovich mechanism for the formation of nitric oxide and the soot model suggested by Hiroyasu et al. were used to predict the diesel emissions. In this paper, the computational results of fuel spray, cylinder pressure, and emissions were compared with experimental data, and the optimum EGR rates were sought from the NO and soot emissions trade-off. The results showed that the EGR is effective in suppressing NO but the soot emission was increased considerably by EGR. Using cooled EGR, soot emission could be enhanced without worsening of NO.