• 한국자동차공학회논문집
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• 제16권4호
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• pp.88-96
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• 2008

Effects of the duct inlet guide vane on the flowrate distribution characteristics of the defroster nozzle exit in a defrost duct system were investigated experimentally to design the optimum heating, ventilation and air conditioning (HVAC) system applied in an automotive compartment. A 3-dimensional hot-wire anemometer system was used to measure the velocity field in the vicinity of the defroster nozzle jet flow and the velocity distributions near the windshield interior surface. At first, two cases of with- and without-duct inlet guide vanes were considered as the test condition, and then three cases of the duct inlet guide vane were tested to determine the optimum guide vane shape and their positions. The arrangement of the duct inlet guide vanes has an effect on the improved flowrate distribution at the defroster nozzle exit and near the windshield interior surface. However, the application of the lots of guide vane to control the flow direction leads to increase the flow resistance, resulting in the decreased flowrate issuing from the defroster nozzle. The shape of the duct inlet guide vane affects not only the flowrate distribution between the driver side and the assistant driver side but also the reduction of the flow resistance in the defrost duct system.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.1172-1177
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• 2008

Diverging channel from gas burner exit to the inlet section of Heat Recovery Steam Generator (HRSG) has been re-designed for 1 MW steam supply and power generation system. Three different test geometries have been chosen for the numerical simulation. The existing design for 300 kW HRSG system (CASE B) has been improved by geometry and position changes of inlet guide vanes along with gas velocity entrance angle at the diverging channel inlet (CASE C). Both cases has been compared with the case where hot combustion gas is directly injected without any guide vanes (CASE A). Improved design shows overall uniform velocity and temperature distribution compared to existing design.

• 한국수소및신에너지학회논문집
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• 제24권4호
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• pp.326-333
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• 2013

This paper presents the performance enhancement of a double-inlet centrifugal blower by the shape optimization of an inlet duct. Two design variables, a length of anti circulation vane and an angles of inlet guide, are introduced to improve the inlet flow uniformity leading to the blower performance. Three-dimensional Navier-Stokes equations are used to analyze the blower performance and the internal flow of the blower. From the shape optimization of the inlet duct of the double-inlet centrifugal blower, the optimal positions of each design variable are determined. Throughout the analysis of sensitivity, it is found that the angle of the inlet guide is more effective than the length of the anti-circulation vane to increase flow uniformity at the outlet of the duct. Efficiency and pressure for the optimal inlet duct shape are successfully increased up to 3.55% and 3.2% compared to those of reference blower at the design flow condition, respectively. Detailed flow field inside the blower is also analyzed and compared.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 학술대회
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• pp.148-154
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• 2008

Diverging channel from gas burner exit to the inlet section of Heat Recovery Steam Generator (HRSG) has been re-designed for 1 MW system. To improve the uniformity in velocity and temperature distribution of existing design(Case A and B) of 300 kW HRSG system, two additional test geometries have been chosen for the numerical simulation. At first, gas burner exit section has been centered to the inlet section of boiler(Case C) and uniformity has been improved considerably. Secondly, the diverging channel length can be further reduced for compact geometry with new guide vane design (Case D and E). Proposed design shows overall improvement in uniformity in velocity and temperature distribution compared to existing one.

• 한국전산유체공학회지
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• 제14권3호
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• pp.1-8
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• 2009

Diverging channel from gas engine exit to the inlet section of Heat Recovery Steam Generator (HRSG) has been re-designed for 1 MW system. To improve the uniformity in velocity and temperature distribution of existing design(Case A and B), two additional test geometries have been chosen for the numerical simulation. At first, gas burner exit section has been centered to the inlet section of the boiler(Case C) and uniformity in velocity and temperature distribution has been improved considerably. Secondly, the diverging channel length can be further reduced to compact geometry with new guide vane design (Case D and E). Proposed design shows overall improvement in uniformity in velocity and temperature distribution compared to existing one.

• International Journal of Advanced Culture Technology
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• 제10권3호
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• pp.295-306
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• 2022

The NOx removal performance of the SCR process depends on various factors such as catalytic factors (catalyst composition, shape, space velocity, etc.), temperature and flow rate distribution of the exhaust gas. Among them, the uniformity of the flow flowing into the catalyst bed plays the most important role. In this study, the flow characteristics in the SCR reactor in the design stage were simulated using a three-dimensional numerical analysis technique to confirm the uniformity of the airflow. Due to the limitation of the installation space, the shape of the inlet duct was compared with the two types of inlet duct shape because there were many curved sections of the inlet duct and the duct size margin was not large. The effect of inlet duct shape, guide vane or mixer installation, and venturi shape change on SCR reactor internal flow, airflow uniformity, and space utilization rate of ammonia concentration were studied. It was found that the uniformity of the airflow reaching the catalyst layer was greatly improved when an inlet duct with a shape that could suppress drift was applied and guide vanes were installed in the curved part of the inlet duct to properly distribute the process gas. In addition, the space utilization rate was greatly improved when the duct at the rear of the nozzle was applied as a venturi type rather than a mixer for uniform distribution of ammonia gas.

• 한국가시화정보학회지
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• 제20권3호
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• pp.86-93
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• 2022

An electrostatic precipitator (ESP) is an industrial post processing facility for high efficiency dust mitigation. Uniformity of the flow passing through the inlet duct leading into the main chamber is important for efficient reduction of dust. To examine flow uniformity, this study conducted a numerical analysis of the flow within a scale-down ESP inlet duct. Magnetic resonance velocimetry (MRV) results from a prior study were utilized to validate the Reynolds-averaged Navier-Stokes (RANS) numerical simulations. Both the experimental and computational results displayed a similar recirculation zone shape and normalized velocity profile near the duct outlet for the baseline geometry. To optimize the uniformity of the flow, the number of guide vanes was modified, and the guide vanes were partially extended straight upward. Design evaluation is done based on the outlet velocity distribution and mass flowrate balance between the two outlets. Simulation results indicate that the vane extension is critical for flow optimization in curved ESP ducts.

• 설비공학논문집
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• 제23권8호
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• pp.543-548
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• 2011

New concept of wind energy conversion system is proposed to increase the energy density at a given working space. The quality of wind for wind power generation is depend on its direction and speed. However, the quality is not good on land because wind direction is changeable all the time and the speed as well. The most popularly operated wind turbine system is an axial-flow free turbine. But its conversion efficiency is less than 30% and even less than 20% considering the operating time. In this research, a cross-flow type wind turbine system is proposed with a convergent-divergent duct system to accelerate the low speed wind at the inlet of the wind turbine. Inlet guide vane is also introduced to the wind turbine system to have continuous power generation under the change of wind direction. In here, the availability of wind energy generation is evaluated with the change of the size of the inlet guide vane and the optimum geometry of the turbine impeller blade was found for the innovative wind power generation system.

• 한국환경과학회지
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• 제18권7호
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• pp.755-765
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• 2009

Some sections of the exhaust system to determine the shape of the duct is to suffer the difficulties by space constraints to install new equipment of the environment post-treatment for existing operation of the power plants. In this paper the large duct in flue gas desulfurization equipments of the 500MW coal-fired power plant on the current operation is numerically analyzed from induced draft fan exit to booster up fan inlet section which is in the narrow space of the exhaust system with four times bending and is connected to emergency duct to bypass the exhaust gas on the emergency operation. The procedure and method using computational fluid dynamics are proposed to maintain the stability of the guide vane with the uniform flow and a minimum pressure loss of exhaust gas in the case of normal and emergency operation between the direction of the flow of exhaust gas duct at different.

• 한국환경과학회지
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• 제29권5호
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• pp.457-468
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• 2020

With continuous industrial development, the types, and amount of particulate matter (PM) have been increasing. Since 2018, environmental standards regarding PM have become more stringent. Pulse air jet bag filters are suitable for PM under the 20 ㎛ and, can function regardless of size, concentration and type. Filtration velocity and shape are important factors in the operation and design of the pulse air jet bag filters however, few established studies support this theory. In this research, numerical simulations were conducted based on experimental values and, several methods were employed for minimizing the pressure drop. In the pilot system, as the inlet duct velocity was faster than 19 m/sec, flow was not distributed equally and, re-entrainment occurred due to the hopper directional vortex. The multi-inlet system decelerated the hopper directional vortex by 25 ~ 30%, thereby decreasing total pressure drop by 6.6 ~ 14.7%. The guide vane system blocked the hopper directional vortex, which resulted optimal vane angle of 53°. The total pressure of the guide vane system increased by 0.5 ~ 3% at 1.5 m/min conditions. However, the filtration pressure drop decreased by 4.8 ~ 12.3% in all conditions, thereby reducing the operating cost of filter bags.