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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Transactions of the Korean Society of Mechanical Engineers B
Journal Basic Information
Journal DOI :
The Korean Society of Mechanical Engineers
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Volume & Issues
Volume 35, Issue 12 - Dec 2011
Volume 35, Issue 11 - Nov 2011
Volume 35, Issue 10 - Oct 2011
Volume 35, Issue 9 - Sep 2011
Volume 35, Issue 8 - Aug 2011
Volume 35, Issue 7 - Jul 2011
Volume 35, Issue 6 - Jun 2011
Volume 35, Issue 5 - May 2011
Volume 35, Issue 4 - Apr 2011
Volume 35, Issue 3 - Mar 2011
Volume 35, Issue 2 - Feb 2011
Volume 35, Issue 1 - Jan 2011
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Analysis of the Bioheat Equation Considering Tissue Layers with Sinusoidal Temperature Oscillation on the Skin
Choi, Woo-Lim ; Moon, Sang-Don ; Youn, Suk-Bum ; Im, Ik-Tae ;
Transactions of the Korean Society of Mechanical Engineers B, volume 35, issue 8, 2011, Pages 757~762
DOI : 10.3795/KSME-B.2011.35.8.757
We investigate the transient temperature response in biological tissue whose surface is exposed to alternately varying sinusoidal oscillation. Based on the Pennes bio-heat equation, we apply numerical analysis using a finite element method to find the effects of the physical properties of the skin layers. Three layers of tissue-epidermis, dermis, and subcutaneous-are considered as the solution region. We investigate the effects of different properties of the skin layers on the temperature profile. We also investigate the effects of the perfusion rate for the dermis, which is the most sensitive layer. The results show that the temperature profile of tissue depth has a discontinuous point when different physical properties are used.
High-Efficiency Design of a Ventilation Axial-Flow Fan by Using Weighted Average Surrogate Models
Kim, Jae-Woo ; Kim, Jin-Hyuk ; Lee, Chan ; Kim, Kwang-Yong ;
Transactions of the Korean Society of Mechanical Engineers B, volume 35, issue 8, 2011, Pages 763~771
DOI : 10.3795/KSME-B.2011.35.8.763
An optimization procedure for the design of a ventilation axial-flow fan is presented in this paper. Flow analyses of the preliminary fan are performed by solving three-dimensional Reynolds-averaged Navier-Stokes equations via a finite-volume solver with the shear-stress transport turbulence model as a turbulence closure. Three variables, the hub-to-tip ratio and the stagger angles at the mid and tip spans, are selected for the optimization. The Latin-hypercube sampling method as a design-of-experiments technique is used to generate twenty-five design points within the design space. and the weighted average surrogate models, WTA1, WTA2, and WTA3, are applied for find optimal designs. The results show that the efficiency is considerably enhanced.
Study on Optimization of Generation System in Series HEV Bus
Jung, Dae-Bong ; Min, Kyoung-Doug ; Jo, Yong-Rae ; Lim, Yong-Soo ;
Transactions of the Korean Society of Mechanical Engineers B, volume 35, issue 8, 2011, Pages 773~779
DOI : 10.3795/KSME-B.2011.35.8.773
In order to improve fuel economy and emissions, many studies of HEV have been conducted. However, most of these studies concentrate on parallel or power-split HEVs. Series-type HEVs have some advantages over parallel and power-split HEVs. One is that the engine is operated at high efficiency since the engine and the driveshaft are decoupled. Nevertheless, the optimization of the powertrain system of series HEV has not been specifically addressed. We conduct an optimization of the generation system of a series HEV based on the series HEV bus. The main objectives are to simulate the system and to compare the fuel economies of conventional and optimized generation systems.
Aerodynamic Design and Numerical Study of a Propane-Refrigerant Centrifugal Compressor for LNG Plant
Park, Joo-Hoon ; Lee, Won-Suk ; Shin, You-Hwan ; Kim, Kwang-Ho ; Lee, Yoon-Pyo ; Chung, Jin-Taek ;
Transactions of the Korean Society of Mechanical Engineers B, volume 35, issue 8, 2011, Pages 781~787
DOI : 10.3795/KSME-B.2011.35.8.781
We design a four-stage propane-refrigerant centrifugal compressor for an LNG plant. Using a commercial code, we aerodynamically designed the compressor at each design point of the corresponding stages. We estimated the one-dimensional aerodynamic design output and the three-dimensional shape of the impeller flow passage via three-dimensional flow analysis. In particular, we discuss in detail the flow characteristics of the impeller and the vaneless diffuser passages of the fourth-stage compressor in terms of the velocity fields, the pressure, and the entropy distributions of the flow passages. We include the flow effects of the tip clearance flow, because at this stage the rotating speed and total inlet pressure are higher than those at the other compressor stages are. We carried out performance tests of the designed compressor stages using propane as a refrigerant in the LNG cycle. The practical evaluation could lead to design enhancements in the future.
Study of NO Storage and Reduction on LNT by Micro Bench-Flow Reactor
Yoon, Joo-Wung ; Hwang, Seung-Kwon ; Hwang, In-Goo ; Park, Sim-Soo ; Lee, Jin-Ha ; Yeo, Gwon-Koo ;
Transactions of the Korean Society of Mechanical Engineers B, volume 35, issue 8, 2011, Pages 789~798
DOI : 10.3795/KSME-B.2011.35.8.789
We carry out an experimental investigation to analyze the basic performance of NO(nitric oxide) storage in a lean phase and also analyze the NO reduction achieved by the spraying of reducing agents in the rich phase of the exhaust gas in an LNT(Lean NOx Trap). This is an after-treatment system used to reduce the NOx emissions from a diesel engine. If the stored NO is reduced, we measure the outlet concentration downstream of the LNT. The test LNT material used in the experiments is commercial LNT. After being canned into stainless-steel(SUS304), it was built in a micro bench-flow reactor. Compositions of feed gases, three heated and three no heated gases were sprayed upstream of the LNT to analyze the characteristics. We use various temperatures and space velocities as response variables.
Performance Comparison Study on LFLP and DBLP Daylighting System
Choi, Jeon-Yong ; Kang, Eun-Chul ; Lee, Euy-Joon ;
Transactions of the Korean Society of Mechanical Engineers B, volume 35, issue 8, 2011, Pages 799~804
DOI : 10.3795/KSME-B.2011.35.8.799
The LFLP (Linear Fresnel Light Pipe) system uses a linear Fresnel lens to follow the sun and concentrates the parallel sunlight into a line. A LFLP daylighting system has been developed and updated to a DBLP (Double Blind Light Pipe) daylighting system to improve the overall system efficiency in the morning and afternoon. The new design consists of a double-blind style with a cone-shaped light transformer. The blinds are used to collect the sun`s altitude and azimuth movements through the day. Behind the two sets of blinds is the light transformer, which is based on a parabolic-shaped light concentrator. The light transformer is designed to efficiently deliver light within a thirty-degree radial spread so that the light pipe can internally reflect the light. The results of scale-model tests are encouraging, and the efficiency is three times higher than that of the previous LFLP system.
Numerical Study on the Distribution Characteristics of Aluminum Plate-Fin Heat Exchangers According to the Distributor Aspect Ratio
Lee, Eung-Chan ; Kang, Hoon ; Heo, Jae-Hyeok ; Kim, Yong-Chan ; Park, Jae-Hong ; Cho, Sung-Youl ;
Transactions of the Korean Society of Mechanical Engineers B, volume 35, issue 8, 2011, Pages 805~814
DOI : 10.3795/KSME-B.2011.35.8.805
Aluminum plate-fin heat exchangers (ALPHEs) are widely used in petroleum and gas-treated processes. The performance of the ALPHE is strongly dependent on the distribution characteristics of the header and the distributors of each fluid. In this paper, we define the aspect ratio in the side-entry type distributor and analyze the distribution characteristics using CFD-based numerical methods. The phenomena of velocity deviation and distribution with the aspect ratio and the inlet Reynolds number were analyzed by applying relative and absolute maldistribution parameters, and an optimum aspect ratio with the inlet Reynolds number was presented.
Basic Study on Flame-Stabilization Characteristics in a Multi-Channel Combustor via a Model of a Porous-Media Combustor
Park, Seung-Il ; Lee, Min-Jung ; Kim, Nam-Il ;
Transactions of the Korean Society of Mechanical Engineers B, volume 35, issue 8, 2011, Pages 815~823
DOI : 10.3795/KSME-B.2011.35.8.815
Combustion phenomena in porous media combustors are widely used in industrial fields for the combustion of lowgrade fuels and the regeneration of combustion heat. However, studies of combustion phenomena in porous media have been limited, because these phenomena are difficult to observe, and the configurations of porous media are complex. We propose a simple model combustor: a multi-channel combustor that consists of many layers of combustion channels made of quartz plates. We conducted an experimental observation of the flames in the multi-channel combustor and obtained experimental results for the flame stabilization limits. Flames formulated in the multi-channel combustor showed variation in the spatial distribution depending on the heat transfer between neighboring channels. A simple analytical model was developed and the variation in the flammability limits of the multi-channel combustor was discussed. This study will enhance our understanding of flame behavior in a porous-media combustor.
Dynamic Characterization of Passive Flow-Rate Regulator Using Pressure-Dependent Autonomous Deflection of Parallel Membrane Valves
Doh, Il ; Cho, Young-Ho ;
Transactions of the Korean Society of Mechanical Engineers B, volume 35, issue 8, 2011, Pages 825~829
DOI : 10.3795/KSME-B.2011.35.8.825
We performed a dynamic characterization of passive flow-rate regulators, which compensate for inlet pressure variation and maintain a constant flow rate for precise liquid control in microfluidic systems. To measure the flow rate for a short time, much less than the period of the dynamic inlet pressure, we use the particle image velocimetry (PIV) method. DI water containing fluorescent beads with a
diameter was supplied to the flow-rate regulators, and two successive images of the particles were taken by a pulse laser and a fluorescent microscope to measure the flow velocity. For a dynamic inlet pressure of frequency 60 Hz, the flow velocity was constant with an average of 0.194
0.014 m/s as the inlet pressure varied between 20 kPa to 50 kPa. The flow-rate regulators provided a constant flow rate of
in the frequency range of the inlet pressure from 1 Hz to 60 Hz.
Design of Stable Evaporative Micro-channel Systems Using Expanding Area
Lee, Hee-Joon ; Yao, Shi-Chune ;
Transactions of the Korean Society of Mechanical Engineers B, volume 35, issue 8, 2011, Pages 831~838
DOI : 10.3795/KSME-B.2011.35.8.831
A growing bubble can be squeezed for water, and it will then encounter flow instability, which reverses toward upstream in straight micro-channels. To reduce the flow instability, a micro-channel that expands at the downstream end has been found to be effective. In the expanding area, a growing bubble will tend to move downstream because the net surface tension force of a vapor-liquid interface is inversely proportional to the local radius of curvature. We propose a static flow instability model and validate it experimentally. Moreover, we apply the local-instability parameter concept to the real design of a stable evaporative micro-channel with an expanding area. Based on the localinstability model, we establish a static design for stable expanding evaporative micro-channels.
Effects of Oxygen Enrichment on the Structure of Premixed Methane/Fluorinated Compound Flames
Lee, Ki-Yong ;
Transactions of the Korean Society of Mechanical Engineers B, volume 35, issue 8, 2011, Pages 839~845
DOI : 10.3795/KSME-B.2011.35.8.839
We performed numerical simulations of freely propagating premixed flames at atmospheric pressure to investigate the influence of trifluoromethane on
flames under oxygen enrichment. Trifluoromethane significantly contributed toward a reduction in flame speed, the magnitude of which was larger in terms of the physical effect than the chemical effect. More trifluoromethane could be added and consumed on oxygen-enriched
was decomposed primarily via
played an important role in oxygen-enhanced flames. When an inhibitor was added to oxygen-enriched flames, the position of the maximum concentration of active radicals was shifted to a relatively low temperature range, and the net rate of OH became higher than that of H.
Effects of Oscillating Flow on the Dynamic Behavior of an Artificial Sensory Hair
Park, Byung-Kyu ; Lee, Joon-Sik ;
Transactions of the Korean Society of Mechanical Engineers B, volume 35, issue 8, 2011, Pages 847~853
DOI : 10.3795/KSME-B.2011.35.8.847
Filiform hairs that respond to movements of the surrounding medium are the mechanoreceptors commonly found in arthropods and vertebrates. The hairs function as a sensory system for perceiving information produced by prey, predators, or conspecifics. A mathematical model is proposed, and the parametric analyses for the response of artificial filiform hair are conducted to design and predict the performance of a microfabricated device. The results for the Cytop hair, one of the most popular polymer optical fibers (POFs), show that the fundamental mode has a dominant effect on the hair behavior in an oscillating medium flow. The dynamic behavior of sensory hair is also dependent on the physical dimensions such as length and diameter. It is found that the artificial hair with a high elastic modulus does not show a resonance in the biologically important frequency range.
Numerical Study of Effect of DAF-Tank Shape on Flow Pattern in Separation Zone of Dissolved Air Flotation
Ryu, Gwang-Nyeon ; Park, Sang-Min ; Lee, Ho-Il ; Chung, Mong-Kyu ;
Transactions of the Korean Society of Mechanical Engineers B, volume 35, issue 8, 2011, Pages 855~860
DOI : 10.3795/KSME-B.2011.35.8.855
We numerically simulated a dissolved air flotation (DAF) tank to predict the performance of the pilot facility. The flow was assumed to be two-dimensional and two-phase. The velocity distributions in the separation zones of differently shaped DAFs were compared to find the effect of the shape on the performance. The results showed that the typical flow pattern that appeared in a well-designed DAF-tank was generated in the separation zone of the base model. This flow pattern could be maintained while the baffle height was sufficiently tall regardless of the other geometric parameters. However, the baffle height and angle, the contact zone width, and the perforated plate affected the uniformity of the downward flow in the separation zone. Except for the baffle height, the base model used in this study showed a better uniformity of downward flow than did other models with different geometric parameters.
Error Characteristics of Clamp-on Ultrasonic Flowmeters Depending on Location of Sensors and Downstream Straight Run of Bent Pipe
Lee, Dong-Keun ; Cho, Yong ;
Transactions of the Korean Society of Mechanical Engineers B, volume 35, issue 8, 2011, Pages 861~868
DOI : 10.3795/KSME-B.2011.35.8.861
Flowmeters that measure the amount of fluid passing through conduits must kept accurate by comparison and the periodic calibration. The reference meters used are clamp-on meters that mount sensors on the outer wall of the pipe. They are called 1-path, 2-path or 4-path flowmeters depending on the number of sensors. We selected a flowmeter mainly used for K-water as test a flowmeter. We carried out experiments to find the intrinsic error of the flowmeter and errors in the downstream of a double bent pipe. The results show that there are the sensor locations that meet the tolerance. We suggested the angle of the sensor, the straight run from the downstream of the bent pipe and the number of sensors. So it is possible to improve the water treatment process and increase the accounted water rate by upgraded flow measurement technology.