• Architectural research
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• v.14 no.1
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• pp.11-18
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• 2012

College of Architecture, Georgia Institute of Technology, Atlanta, GA, US Abstract The intermittent heating and cooling energy need calculation of the ISO 13790 monthly method was examined. The current ISO 13790 method applies a reduction factor to the continuous heating and cooling need calculation result to derive the intermittent heating and cooling for each month. This paper proposes a method for the intermittent energy need calculation based on the internal mean temperature calculation. The internal temperature calculation procedure was introduced considering the heat-balance taking into account of heat gain, heat loss, and thermal inertia for reduced heating and cooling period. Then, the calculated internal mean temperature was used for the intermittent heating and cooling energy need calculation. The calculation results from the proposed method were compared to the current ISO 13790 method and validated with a dynamic simulation using EnergyPlus. The study indicates that the intermittent heating and cooling energy need calculation method using the proposed model improves transparency of the current ISO 13790 method and draws more rational outcomes in the monthly heating and cooling energy need calculation.

• Steel and Composite Structures
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• v.35 no.6
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• pp.729-737
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• 2020

The goal of this study is to investigate dynamic responses of laminated composite beams under a moving load with thermal effects. The governing equations of problem are derived by using the Lagrange procedure. The transverse-shear strain and rotary inertia are considered within the Timoshenko beam theory. The material properties of laminas are considered as the temperature dependent physical property. The differential equations of the problem are solved by the Ritz method. The solution step of dynamic problem, the Newmark average acceleration method is used in the time history. A compassion study is performed for accuracy of used formulations and method. In the numerical results, the effects of velocity of moving load, temperature values, the fiber orientation angles and the stacking sequence of laminas on the dynamic responses of the composite laminated beam are investigated.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.2105-2108
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• 2003

The characteristics of upward bubble flow were experimentally investigated in a liquid bath. In the present study, a thermal-infrared camera and high speed CCO camera were used to measure their temperature and local rising velocity, respectively. Heat transfer from bubble surface to water is largely completed within z=10mm from the nozzle, and then the temperature of bubble surface reaches that of water rapidly. The rising velocity of bubble was calculated for two different experimental conditions: 1) bubble flow without kinetic energy 2) with kinetic energy. Bubble flow without kinetic energy starts to undergo the effect of inertia force 10cm away from the nozzle. Whereas, kinetic energy is dominant before 30 cm away from the nozzle in bubble flow, but after this point, kinetic energy and inertial force are applied on bubble flow at the same time.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.399-406
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• 2001

Thermally induced vibration response of composite thin walled beams is investigated. The thin-walled beam model incorporates a number of nonclassical effects of transverse shear, primary and secondary warping, rotary inertia and anisotropy of constituent materials. Thermally induced vibration response characteristics of a composite thin walled beam exhibiting the circumferentially uniform system(CUS) configuration are exploited in connection with the structural bending-torsion coupling resulting from directional properties of fiber reinforced composite materials and from ply stacking sequence. A coupled thermal structure analysis that includes the effects of structural deformations on heating and temperature gradient is investigated.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.12
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• pp.1668-1678
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• 1997

Numerical analyses were performed to investigate the characteristics of regenerator in oscillating flow by using moving boundary method and Darcy model. In this work, periodic adiabatic boundary condition was suggested as the boundary condition of adiabatic part so that the effects of the thermal inertia of the wall could be considered. In carrying out numerical analyses, two models were applied and compared. One called isotropic model has the same thermal conductivity in radial and axial directions within a porous media. The other called aeolotropic model has different conductivity in each directions. Isotropic model could not show the advantage of energy reduction which needs to maintain constant wall temperature difference between heater and cooler. But aeolotropic model could simulate the reduction of energy consumption.

• International Journal of Aeronautical and Space Sciences
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• v.1 no.2
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• pp.22-29
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• 2000

A method to simulate the gas turbine transient behavior is developed. The basic principles of the method and main input data required are described. Calculation results are presented in terms of whole operating regime of the engine. The influence of initial parameters such as starting engine power, moment of inertia of the rotor, fuel schedule on performance characteristics of gas turbine during transient operation is shown. In addition, the effect of bleeding air on transient behavior is also considered. For validation of the developed computer code, a comparative analysis with experimental data obtained from a heavy duty gas turbine is made. Calculation results agree well with the experimental data for the range of operating regime studied and proved applicability of the developed technique to initial design stage of control system.

• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2307-2309
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• 2002

A simulator had been developed and will be used for reliability verification on turbine control programs for boiler feed pump in power plant prior to its actual operation in field. A mathematical model on thermal dynamics pertaining to prime mover steam turbine and pump was realized and included in this simulator. Also, many design and operating data acquired from fields were utilized in order to decide mechanical and thermal dynamic characteristics such as friction loss windage loss and inertia. A user can decide closing or opening velocity of steam stop valves and steam regulation valves. This simulator is able to generate steam pressure, turbine speed, pump power.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2578-2580
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• 2000

A siumlator had been developed and used for reliability verification on medium size steam turbine control programs prior to its actual operation in field. A mathematical model on thermal dynamics pertaining to prime mover steam turbine and electrical generator was realized and included in this simulator. Also, many operating data acquired from fields was utilized in order to decide mechanical and thermal dynamic characteristics such as friction loss, windage loss and inertia. A user can decide closing or opening velocity of steam stop valve and steam regulation valve. This simulator is able to generate steam pressure, turbine speed, electrical power, and power system frequency.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2138-2140
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• 2001

A siumlator had been developed and will be used for reliability verification on large steam turbine control programs prior to its actual operation in field. A mathematical model on thermal dynamics pertaining to prime mover steam turbine and electrical generator was realized and included in this simulator. Also, many operating data acquired from fields was utilized in order to decide mechanical and thermal dynamic characteristics such as friction loss, windage loss and inertia. A user can decide closing or opening velocity of steam stop valves and steam regulation valves. This simulator is able to generate steam pressure, turbine speed, electrical power, and power system frequency.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.5
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• pp.1237-1245
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• 1993

In this study, a model of a flat plate solar collector using a heat pipe was manufactured and tested to investigate such operational characteristics of the present system of solar collector as start-up process, temperature distribution on the absorber plate and operation of the heat pipe. Moreover, collector efficiency was measured for 20-30 minutes of operation at various conditions of weather and the result was compared with that tested by Hill et. a. for a flat plate solar collector using direct circulation of coolant. Some results obtained in this study could be summarized as follows. (1) The required time for the initial start-up process was about 5-6 minutes, but the heat pipe began to operate as soon as the absorber plate was exposed to solar radiation. (2) On the absorber plate, the temperature distributions in axial direction maintained nearly constant, while temperature distributions in transversal direction showed smooth decrease with $3-5^{\cird}C$ along with solar radiation. (3) Thermal inertia of the collector system had a favorable effect to damp the turbulent variation of solar radiation. (4) The collector efficiency of the present system showed nearly the same tendency but a decrease of about 10% compared with that using direct circulation of coolant.