• Coupled systems mechanics
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• v.11 no.1
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• pp.43-54
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• 2022

In order to analyse the thermal performance of battery systems in electric vehicles complex simulation models with high computational cost are necessary. Using reduced order methods, real-time applicable model can be developed and used for on-board monitoring. In this work a data driven model of the cooling plate as part of the battery system is built and derived from a computational fluid dynamics (CFD) model. The aim of this paper is to create a meta model of the cooling plate that estimates the temperature at the boundary for different heat flow rates, mass flows and inlet temperatures of the cooling fluid. In order to do so, the cooling plate is simulated in a CFD software (ANSYS Fluent ®). A data driven model is built using the design of experiment (DOE) and various approximation methods in Optimus ®. The model can later be combined with a reduced model of the thermal battery system. The assumption and simplification introduced in this paper enable an accurate representation of the cooling plate with a real-time applicable model.

• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.320-325
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• 2010

A multiphase CFD analysis is performed to investigate the effect of near-wall grid for simulating a subcooled boiling flow in vertical tube. The multiphase flow model used in this CFD analysis is the two-fluid model in which liquid(water) and vapor(steam) are considered as continuous and dispersed fluids, respectively. A wall boiling model is also used to simulate the subcooled boiling heat transfer at the heated wall boundary. The diameter and heated length of tube are 0.0154 m and 2 m, respectively. The system pressure in tube is 4.5 MPa and the inlet subcooling is 60 K. The near-wall grid size in the non-dimensional wall unit ($y_{w}^{+}$) was examined from 64 to 172 at the outlet boundary. The CFD calculations predicted the void distributions as well as the liquid and wall temperatures in tube. The predicted axial variations of the void fraction and the wall temperature are compared with the measured ones. The CFD prediction of the wall temperature is shown to slightly depend on the near-wall grid size but the axial void prediction has somewhat large dependency. The CFD prediction was found to show a better agreement with the measured one for the large near-wall grid, e.g., $y_{w}^{+}$ > 100.

• Journal of Korean Society of Water and Wastewater
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• v.19 no.4
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• pp.421-428
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• 2005

Dissolved air flotation (OAF) is a solid-liquid separation system that uses fine bubbles rising from bottom to remove particles in water. In this study, we investigated the effect of L/W (L; Length, W; Width) on the hydro-dynamic behavior in DAF system using CFD (Computational Fluid Dynamics) and ADV (Acoustic Doppler Velocimetry) technique. The factual full-scale DAF system, L/W ratio of 1:1, was selected and various L/W ratio (2:1, 3:1, 4:1 and 5:1) conditions were simulated with CFD. For modelling, 2-phase (gas-liquid) flow equations for the conservation of mass, momentum and turbulence quantities were solved using an Eulerian-Eulerian approach based on the assumption that very small particle is applied in the DAF system. Also, for verification of CFD simulation results, we measured the factual velocity at some points in the full-scale DAF system with ADV technique. Both the simulation and the measurement results were in good accordance with each other. As the results of this study, we concluded that L/W ratio and outlet geometry play important role for flow pattern and fine bubble distribution in the flotation zone. In the ratio of 1:1, the dead zone is less than those in other cases. On the other hands, in the ration of 3:1, the fine bubbles were more evenly distributed.

• Korean Chemical Engineering Research
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• v.48 no.5
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• pp.598-602
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• 2010

In this paper, we carried out CFD modelling and simulation for the membrane system to separate H2 gas from the multi-component feed gas. The membrane system is of the annulus tubular type consisting of the external lumen side for the feed gas and the internal permeation side for the sweeping gas. The operating temperature and pressure of the lumen side inlet flow are $374^{\circ}C$ and 7 bar respectively and those of the sweeping gas are $374^{\circ}C$ and 3 bar, and considering these conditions, Pd membrane system was employed. CFD simulations were performed for the co-current flow and counter-current flow membrane system based on the flow directions between the feed and the sweeping gas. Comparisons and discussions were made for the H2 partial pressure, H2 mole fraction and H2 flux for both cases. Furthermore, we executed CFD simulations for the each case of the various inlet flow rates of the feed gas at the lumen side. Accordingly, we reviewed the effects of the flow rate and residence time on the performance of the membrane system.

• Journal of Bio-Environment Control
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• v.11 no.2
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• pp.93-100
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• 2002

This study was carried out not only to develop CFD model for numerically simulating fog cooling system but also to verify the validity of the developed model by data measured in fag cooling greenhouse. In addition the developed model was applied to investigate the effects of spraying water temperature, spraying water amount, spraying interval and evaporation percentage on the performance of the fog cooling system. According to the simulation results, the temperature differences between the measured and predicted temperatures at each measurement point were $0.1~1.4^{\circ}C$ in case of no shading and $0.2~2.3^{\circ}C$ in close of shading. The humidity differences were 0.3~6.0% and 0.7~10.6%, respectively in the cases of no shading and shading. Because the predicted data showed a good agreement with the measured ones, the developed model is supposed to be able to predict the cooling effect of the fog cooling system. The performance of fog cooling system was greatly influenced by spraying water amount, spraying interval and evaporation percentage, but it was not influenced by spraying water temperature.

• Journal of the Korea Institute of Military Science and Technology
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• v.24 no.6
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• pp.629-637
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• 2021

For the stabilization of laser output power and wavelength of the high power fiber laser, the cooling plate must be properly taken into account. In this study, three analyzing methods which are heat transfer theory, CFD and experiment are used to analyze cooling plate performance by measuring pump Laser Diode(LD) temperature. Under limited operating conditions of a cooling plate, the internal flow of cooling plate is transitional flow so that the internal flow is assumed to be laminar and turbulence flow and conducted theoretical calculation. Through CFD, temperature of pump LD and characteristics of the internal flow were analyzed. By the experiment, temperature of pump LD was measured in real conditions and the performance of the cooling plate was verified. The results of this study indicate that three analyzing methods are practically useful to design the cooling plate for the high power fiber laser or similar things.

• Journal of Aerospace System Engineering
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• v.6 no.4
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• pp.24-28
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• 2012

In this paper, 2-D experiment and steady-state computational fluid analysis were conducted for measuring the hear transfer coefficient of pintle type controllable thruster in high pressure and temperature. In case of 2-D experiment, transient liquid crystal technique was used for measuring heat transfer coefficient for the 2-D pintle model. The experimental result was used to validate the CFD result. The CFD results well predicted the heat transfer coefficient on the pintle surface except the nozzle downstream region, where the results by CFD was higher than experimental results. The CFD results were also compared with the result by Bartz equation and the it was shown that the Bartz equation overestimated the heat transfer coefficient on the nozzle throat as much as 80%.

• 한국전산유체공학회:학술대회논문집
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• 2000.10a
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• pp.92-100
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• 2000

At the end of 1999. the TeraCluster project has started in the KORDIC Supercomputer center to study PC clusters for parallel computing. The aim is to replace the Cray T3E with a new cluster system in 2002. The PC cluster without a fast network is well suited for applications which do not require large amount of global communications. Since CFD problems are not very communication intensive, whole test cluster may be efficiently used. As an example of practical CFD simulations. the flow past the ONERA M6 wing and the flow past infinite wing are simulated on a cluster of Linux workstations.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.51 no.2
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• pp.155-162
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• 2015

Abalone (Haliotis discus hannai) is a shellfish that feeds on kelp and, as a product, it can often achieve a high market value. However, the dissolved oxygen (DO) levels in coastal waters in Korea have been negatively impacted by pollution from many anthropogenic sources. Herein, a computational fluid dynamics (CFD) software package was used to analyze the distribution of the DO concentration within an abalone containment structure. A finite volume approach was used to solve the Reynolds-averaged Navier-Stokes equations combined with a $k-{\varepsilon}$ turbulence model to describe the flow. The distribution of DO was determined within the control volume domain, and the transport equations of the pollutants were interpreted using a CFD model. The CFD analysis revealed that more than 60% and 30% of the relative oxygen concentration in one and two containers, respectively, was maintained when the flow acts along the six sheets of polyethylene plates. Therefore, it is clear that the abalone plate shelters should be placed parallel to the flow.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.32 no.5
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• pp.392-399
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• 2008

Accurate measurement of speed and altitude of flying vehicles in air data system remains a critical technical issue. A highly reliable Pitot-static probe is required to obtain air data such as total pressure and static pressure. In this study, an analysis of the characteristics of flowfield around the Pitot-static probe was performed by using a Navier-Stokes CFD code. In addition, for the purpose of finding an optimal configuration, a technique based on the response surface method is applied to the problem with design parameters including shape of the nose section and cone angle. It is shown that the optimal configuration fulfills the MIL specification in wider range of high angles of attack.