• Title/Summary/Keyword: numerical manifold method

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Pressure Variations in Intake and Exhaust Manifold of a Single Cylinder Engine (단기통 엔진의 흡.배기계의 압력 변동에 관한 연구)

  • Choi, Seuk-Cheun;Lee, Young-Hun;Lee, Sang-Chul;Chung, Han-Shik;Lee, Kwang-Young;Jeong, Hyo-Min
    • Proceedings of the KSME Conference
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    • 2003.11a
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    • pp.775-780
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    • 2003
  • In this study, a computer analysis has been developed for predicting the pipe pressure of the intake and exhaust manifold in a single cylinder engine. To get the boundary conditions for a numerical analysis, one dimensional and unsteady gas dynamic calculation is performed by using the MOC(Method Of Characteristic). The main numerical parameters are the variation of the exhaust pipe diameters to calculate the pulsating flow when the intake and exhaust valves are working. As the results of numerical analysis, the shapes and distributions of the exhaust pipe pressures were influenced strongly on the cylinder pressure. As the exhaust pipe diameter is decreased, the amplitude of exhaust pressure is large and the cylinder pressure was showed low in the region of intake valve opening time.

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Thermal Fatigue Life Prediction of Engine Exhaust Manifold (엔진 배기매니폴드의 열피로 수명 예측)

  • Choi, Bok-Lok
    • Transactions of the Korean Society of Automotive Engineers
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    • v.15 no.1
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    • pp.139-145
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    • 2007
  • This paper presents the low cycle thermal fatigue of the engine exhaust manifold subject to thermomechanical cyclic loadings. The analysis includes the FE model of the exhaust system, temperature dependent material properties, and thermal loadings. The result shows that at an elevated temperature, large compressive plastic deformations are generated, and at a cold condition, tensile stresses are remained in several critical zones of the exhaust manifold. From the repetitions of thermal shock cycles, plastic strain ranges could be estimated by the stabilized stress-strain hysteresis loops. The method was applied to assess the low cycle thermal fatigue for the engine exhaust manifold. It shows a good agreement between numerical and experimental results.

Flow Distribution in Manifold Using Modified Equal Pressure Method (수정된 등압법을 이용한 매니폴드의 유량분배)

  • Ye, Huee-Youl;Kim, Doo-Hwan;Lee, Kwan-Soo;Cha, Woo-Ho
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.21 no.3
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    • pp.176-185
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    • 2009
  • A general flow distribution model and a simple process of numerical analysis, which can be applied to multi-pass systems with manifolds, are presented. A numerical procedure, namely a modified equal pressure method based on the discrete model, was developed to predict flow rates at branch tubes. The predicted pressure distribution agreed well with the previous research with the average error less than 11%. A parametric study was performed to demonstrate the effect on the flow distribution.

PARALLEL SHRINKING PROJECTION METHOD FOR FIXED POINT AND GENERALIZED EQUILIBRIUM PROBLEMS ON HADAMARD MANIFOLD

  • Hammed Anuoluwapo Abass;Olawale Kazeem Oyewole
    • Communications of the Korean Mathematical Society
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    • v.39 no.2
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    • pp.421-436
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    • 2024
  • In this article, we propose a shrinking projection algorithm for solving a finite family of generalized equilibrium problem which is also a fixed point of a nonexpansive mapping in the setting of Hadamard manifolds. Under some mild conditions, we prove that the sequence generated by the proposed algorithm converges to a common solution of a finite family of generalized equilibrium problem and fixed point problem of a nonexpansive mapping. Lastly, we present some numerical examples to illustrate the performance of our iterative method. Our results extends and improve many related results on generalized equilibrium problem from linear spaces to Hadamard manifolds. The result discuss in this article extends and complements many related results in the literature.

Development of a numerical flow model for the multi-cylinder engine intake system (다기통 엔진 흡기시스템의 유동해석 모델개발)

  • Song, Jae-Won;Seong, Nak-Won
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.20 no.6
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    • pp.1921-1930
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    • 1996
  • To design an optimum engine intake system, a flow model for the intake manifold was developed by the finite difference method. The flow in the intake manifold was one-dimensional, and the finite difference equations were derived from governing equations of flow, continuity, momentum and energy. The thermodynamic properties of the cylinder were found by the first law of thermodynamics, and the boundary conditions were formulated using steady flow model. By comparing the calculated results with experimental data, the appropriate boundary conditions and convergence limits for the flow model were established. From this model, the optimum manifold lengths at different engine operating conditions were investigated. The optimum manifold length became shorter when the engine speeds were increased. The effect of intake valve timings on inlet air mass was also studied by this model. Advancing intake valve opening decreased inlet air mass slightly, and the optimum intake valve closing was found. The difference in inlet air mass between cylinders was very small in this engine.

Velocity Control of Permanent Magnet Synchronous Motors Using Nonlinear Sliding Manifold (영구 자석형 동기모터 속도제어를 위한 비선형 슬라이딩 매니폴드 설계)

  • Gil, Jeonghwan;Shin, Donghoon;Lee, Youngwoo;Chung, Chung Choo
    • Journal of Institute of Control, Robotics and Systems
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    • v.21 no.12
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    • pp.1136-1141
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    • 2015
  • In this paper, we develop a sliding mode controller that uses a nonlinear sliding manifold for the permanent magnet synchronous motor. The proposed controller makes sure that both currents and velocity tracking error converge into equilibria. Nonlinear sliding manifold consists of current dynamics and nonlinear functions which are designed with velocity tracking error and its integrated term. The nonlinear functions are designed to guarantee that velocity tracking error converge into zero. The closed-loop stability is proven by Lyapunov theory. The effectiveness of proposed method is demonstrated by numerical simulation results.

The pulsating pressure in the intake and exhaust manifold of a single cylinder engine by the various of engine revolutions

  • Chung, Han-Shik;Choi, Seuk-Cheun;Jong, Hyo-Min;Lee, Chi-Woo;Kim, Chi-Won
    • Journal of Advanced Marine Engineering and Technology
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    • v.28 no.1
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    • pp.75-82
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    • 2004
  • In this research, a computer analysis has been developed for predicting the Pipe pressure of the intake and exhaust manifold in a small single cylinder engine. To get the boundary conditions for a numerical analysis one dimensional and unsteady gas dynamic calculation is performed by using the MOC(Method Of Characteristics). The main numerical parameters are engine revolutions. to calculate the Pulsating flow which the intake and exhaust valves are working. The distributions of the exhaust pipe pressures were influenced strongly to the cylinder pressures and the shapes of exhaust pressure variation were similar to the Inside of cylinder pressure As the engine revolutions are increased. the intake pressure was lower than ambient pressure. The amplitude of exhaust pressure had increased and the phase of cylinder pressure $P_c$ is delayed and the amplitude of cylinder pressure were increased.

Simulation of the fracture of heterogeneous rock masses based on the enriched numerical manifold method

  • Yuan Wang;Xinyu Liu;Lingfeng Zhou;Qi Dong
    • Geomechanics and Engineering
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    • v.34 no.6
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    • pp.683-696
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    • 2023
  • The destruction and fracture of rock masses are crucial components in engineering and there is an increasing demand for the study of the influence of rock mass heterogeneity on the safety of engineering projects. The numerical manifold method (NMM) has a unified solution format for continuous and discontinuous problems. In most NMM studies, material homogeneity has been assumed and despite this simplification, fracture mechanics remain complex and simulations are inefficient because of the complicated topology updating operations that are needed after crack propagation. These operations become computationally expensive especially in the cases of heterogeneous materials. In this study, a heterogeneous model algorithm based on stochastic theory was developed and introduced into the NMM. A new fracture algorithm was developed to simulate the rupture zone. The algorithm was validated for the examples of the four-point shear beam and semi-circular bend. Results show that the algorithm can efficiently simulate the rupture zone of heterogeneous rock masses. Heterogeneity has a powerful effect on the macroscopic failure characteristics and uniaxial compressive strength of rock masses. The peak strength of homogeneous material (with heterogeneity or standard deviation of 0) is 2.4 times that of heterogeneous material (with heterogeneity of 11.0). Moreover, the local distribution of parameter values can affect the configuration of rupture zones in rock masses. The local distribution also influences the peak value on the stress-strain curve and the residual strength. The post-peak stress-strain curve envelope from 60 random calculations can be used as an estimate of the strength of engineering rock masses.

Basic Design of Subsea Manifold Suction Bucket (심해저 원유 생산용 매니폴드 기초 석션 버켓 기본 설계)

  • Woor, Sun-Hong;Lee, Kangsu;Choung, Joonmo
    • Journal of the Society of Naval Architects of Korea
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    • v.55 no.2
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    • pp.161-168
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    • 2018
  • This paper presents the design procedure of the suction bucket used to support a subsea manifold. The soil-suction bucket interaction numerical analysis technique was verified by comparing the present results with a reference data. In order to simulate the soil-bucket interaction analyses of a subsea manifold structure, various material data such as undrained shear strength, elastic modulus, and poisson ratio of soft clay in Gulf of Mexico were collected from reference survey. We proposed vertical and horizontal design loads based on system weights and current-induced drag forces. Under the assumption that diameter of the suction bucket was 3.0 m considering real dimension of the subsea manifold frame structures, aspect ratio was decided to be 3.0 based on reference survey. The ultimate bearing load components were determined using tangent intersection method. It was proved that the two design load components were less than ultimate bearing loads.

Numerical simulation for the gas exchange process of 4-cycle single cylinder diesel engine (단기통 4행정 디젤기관의 흡배기과정 시뮬레이션 연구)

  • 이재순;이재규
    • Journal of the korean Society of Automotive Engineers
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    • v.12 no.3
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    • pp.30-40
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    • 1990
  • The computer program for the prediction of the volumetric efficiency of 4-cycle single cylinder diesel engine was developed using the characteristic method which considers the effects of friction, heat transfer and specific heat. The results of calculation by this program are as follows; 1. The back flowing was arised at the beginning and the closing stage of inlet valve, and the back flowing mass and velocity decrease as the engine speed increases. 2. The volumetric efficiency varies with the engine speed and the length of inlet manifold. There was an optimum length of inlet manifold for each specified engine speed. 3. The pressure fluctuation and friction effect in the inlet manifold became very important factors for the determination of the volumetric efficiency.

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