Charoensuk, Jarruwat

Preferred name

Alternative Name

Charoensuk, J.

Charoensuk, Jaruwat

Main Affiliation

School of Engineering

jarruwat.ch@kmitl.ac.th

Now showing 1 - 10 of 14

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Numerical simulation of metal-supported solid oxide fuel cell (mSOFC)
(2009-12-01)
Phoocharoen, Niwat
;
Charoensuk, Jarruwat
In this paper we present the numerical results of planar solid oxide fuel cell at the level of membrane electrode assembly, MEA. The study is aimed at evaluating the performance of metal-supported design versus the conventional anode-cathode support under co-flow and counter-flow conditions. We have found that the value of peak temperature is lower therefore better temperature distribution is achieved for metal supported design with counter-flow configuration. Moreover the corresponding current density at maximum power is also higher with this configuration. This later design however possesses greater concentration loss or over-potential due to fuel concentration gradient at the porous layer of supporting metal. To compensate this difference, we have proposed the modification of the current collector at the cathode side to reduce the ohmic loss, while minimizing the concentration loss at the reaction site. The result of this modification suggests an improvement of maximum power density from 0.984 W/cm2 to 1.034 W/cm2. This is slightly less than the value of an original version for only 0.132 %. At this counter-flow configuration the value of peak temperature is also lower as compared with its counterpart with co-flow configuration. Copyright © 2009 by ASME.
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Behaviour of various glass seal for planar solid oxide fuel cell
(2008-01-01)
Punbusayakul, N.
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Wongklang, W.
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Wongtida, K.
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Charoensuk, J.
;
Charojrochkul, S.
One of the critical issues in designing a planar solid oxide fuel cell (SOFC) is the development of materials to hermetically seal the metal (430 series stainless steel) or ceramic interconnector with the ceramic electrolyte of the cell. The main objective of this sealing material is to achieve a low leak rate, long-term stability at operating temperature and chemical compatibility with other components. One of the compositions has been operated in an SOFC in excess of 30 minutes over the range of 600, 700, 800, and 900°C. The seal is a composition of polymer blend and glass of 1:3, 1:1 and 3:1 by weight. The leakage rate of each seal was measured simultaneously under the compressive force of 100 N, 2 bar Helium. The seal was characterized using a thermogravimetric analysis. The effect of glass composition on operating temperature and compressive forces on the leakage rate have been discussed and correlated. © 2008 Trans Tech Publications, Switzerland.
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Effects of sintering time and atmosphere on mechanical properties of injection molded Tungsten alloy
(2013-01-01)
Lamlerttham, Jittrabhanu
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Wila, Pongsak
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Morakotjinda, Monnapas
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Krataitong, Rungtip
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Vetayanukul, Bhanu
Tungsten is a promising refractory metal suitable for applications in which wear resistance, thermal stability and high weight are needed. In this work, the tungsten feedstock (94wt%W with balance of Ni-Cu-Co alloy) was used to form tensile test specimens by using metal injection molding (MIM) process. The molded specimens were debinded by catalytic debinding technique to convert to the brown specimens. After debinding, the brown parts were sintered under vacuum atmosphere (10-5 bar) with varied sintering times at sintering temperature from 1350 to 1450°C. The specimens sintered at 1450°C for 3 hours provided optimum sintered density and mechanical properties. The results showed that mechanical properties of the specimens sintered at 1450°C dramatically decreased when sintering times were longer than 3 hours. The specimens sintered at 1450°C for 8 hours showed brittleness. Physically, inferior mechanical properties were attributed to wettability and porosity of the binder phase. Chemical analyses were performed with the sintered W-(Ni-Cu-Co) specimens by using energy dispersive spectroscopy with mode of quantitative analysis. The specimens sintered at 1400°C for 3 hours showed high W content (28.95 wt. %) dissolved in the Ni-Cu-Co binder. However, penetration of the liquid binder was incomplete. The specimens sintered at 1450°C for 3 hours showed higher W content (34.28 wt. %) dissolved in the Ni-Cu-Co binder (with lower Cu content). Distribution of Cu was uniform across the whole specimen. Wetting of the liquid binder on W grains was complete without porosity. The specimens sintered at 1450°C for longer than 3 hours showed less W content (< 28.95 wt. %) dissolved in the Cu-depleted Ni-Co binder. Porosity was observed in the binder phase and in W grains. Sintering between W grains was also observed. Effects of different sintering atmospheres were also investigated. It was found that increasing the sintering chamber pressure caused detrimental effects on both physical and mechanical properties of the sintered tungsten specimens. In addition, nitrogen atmosphere gave similar results to those for increased chamber pressure. © (2013) Trans Tech Publications.
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Effect of hydrogen purging period on system performance of PEMFC
(2010-07-30)
Pokphet, T.
;
Khan-ngern, W.
;
Charoensuk, J.
This paper concerns with the study on the effect of hydrogen Purging period on the performance of PEMFC system. It is aimed to improve PEMFC performance to be a reliable power source for power supply unit. The membrane electrode assembly of a PEMFC (Proton Exchange Membrane Fuel Cell) has to be wet for the fuel cells to work efficiently. Despite many factors causing cell degradation and jeopardize the stack performance and attenuate the electrochemical reaction, this paper only focuses on an arrangement of hydrogen purging period to remove water droplets and residue of inert gas from the anode side of the fuel cell. Experiments show the stack performance as well as its efficiency at various purging periods at 100 W and 400 W loads.
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Influence of non-straight parallel channel designs on performance of planar SOFC
(2009-12-01)
Wattana, Wassachol
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Charoensuk, Jarruwat
;
Charojrochkul, Sumittra
The flow aerodynamic and friction loss which are usually considered for heat exchanger design are adapted for a channel design for solid oxide fuel cell stack. In this study the design concept is limited to a parallel configuration because of its simplicity. Heat and mass transfer rate can be improved by an introduction of the non-straight parallel channel design yielding higher fuel cell performance. In this paper, a three-dimensional computational model of SOFCs with non-straight parallel channel has been constructed using computational aided engineering tool, FLUENT. The aim of this work is to investigate the cell performance associated with underlying transport phenomena of different channel configurations by looking at distributions of velocity, pressure, hydrogen and oxygen concentrations and current density of each channel design. The influence of each flow channel design (serpentine-parallel, zigzag-parallel and wavy-parallel) on cell performance in SOFCs is discussed. The results indicate that the most enhanced cell performance, especially at high current density, is achieved by using a serpentine-parallel channel design with a trade-off on its greater pressure drop. Copyright © 2009 by ASME.
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CFD based Improvement of Thai Irrigation Pump
(2020-01-01)
Wasinarom, Kittipass
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Boonchauy, Dachdanai
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Charoensuk, Jarruwat
Evaluation phase which was partial fulfilment of the beginning phase of "Development of Performance test rig and Efficiency improvement of impeller in Thai irrigation pump project" is presented in this paper. Overall flow field in the pump system that consisted of inlet, impeller and stator vane of the available pump was analyzed using commercial Computational Fluid Dynamics (CFD) code. The goal of this investigation is to obtain more understanding of energy dissipation which results from shear stress that developed within the flow field in each section of the pump. The improvement measure is then conducted with the concern of manufacturing difficulties. High dissipation flow structure was observed around the impeller outlet. Jet-wake and recirculation flow were observed. The first improvement measure was conducted by adding the bluff body in the flow channel to alleviate jet-wake structure and delay flow separation. After the implementation of the optimized bluff body around the impeller exit, CFD results indicated around 3-8% improvement compared with the CFD results of the available pump for the entire range of operating conditions.
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Numerical analysis on water activities at catalyst-interfaces in PEM fuel cell with phase change
(2011-06-13)
Suttanarak, Keerasut
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Uthaichana, Kasemsak
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Naksuk, Nirut
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Charoensuk, Jarruwat
The analysis on the activities of water inside a low temperature Proton Exchange Membrane (PEM) fuel cell during its operation is set forth in this paper. The simulation model is of two-phase (vapor/liquid), three-dimensional (3-D) covering the transport phenomena such as water source term, electro osmotic drag, water back diffusion as well as the temperature distribution. The serpentine channel design with co-flow feed is considered in this investigation. The gas humidification and other settings are deliberately set so that water condensation can occur. The formulated finite-element based PEM fuel cell model is amenable to numerical techniques, such as direct collocation discretization. The simulation results from the 3-D simulator are presented as a set of various (cut) slices in two-dimensional (2-D) space. The distributions of each term in 3-D at the triple phase boundary (TPB)-the reaction site on the catalyst surface, and at the interface between the gas diffusion layer (GDL) and the flow channel help us to identify areas where water condensation is likely and least likely to occur. The obtained information is useful for improving algorithms in the control and diagnostics software for the PEM fuel cell.
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Total energy requirement for hydrogen production reactor using various porous media materials
(2015-01-01)
Srilomsak, Mek
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Aungkharuengrattana, Waroht
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Sesuk, Thanathon
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Charoensuk, Jarruwat
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Charochrojkul, Sumittra
In a hydrogen production reactor, combustion of LPG was used as a heat source for ethanol steam reforming. For such purpose, the operating temperature was required to be around 700-900 °C along the entire height of the reactor. Various types of porous media materials were used as a heat transfer media, i.e. 25mm ceramic saddles, random size bio-filter media from MTEC, ceramic foam, and ceramic balls. The objective of this study was to obtain the practical amount of total energy input, to compare with theoretical calculation which can achieve the required temperature of ethanol steam reforming for the hydrogen production. From our experiments, 13.20 kW of energy was needed to fulfill the requirement of the reactor, while only 2.49 kW was expected from theoretical calculation. Most energy loss was due mainly to: 1) heat loss at the top of the reactor where the metal part was directly exposed to the environment, 2) a large amount of energy loss at the furnace stack and, 3) insufficient mixing at the early stage of combustion at the bottom of the furnace as noticed by high CO concentration in flue gas. The porous media material has a significant effect on temperature distribution and energy consumption. The results show that the use of ceramic saddles as porous media consume more energy than the ceramic foam and the bio-filter media mixed with ceramic saddles during the start-up period of the reactor.
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Non-reacting flow distributions under various SOFC stack configurations
(2007-12-01)
Wattana, Wassachol
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Charoensuk, Jarruwat
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Phoocharoen, Niwat
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Charojrochkul, Sumittra
A 3-dimensional Computational Fluid Dynamics (CFD) model for fuel cell stack simulations has been developed using STAR-CD with effect of buoyancy force. A flow distribution in a planar fuel cell stack with straight gas channels is considered with variation in gas feeding directions. Any electrochemical interaction is neglected. Eight flow configurations comprising of three parameters were investigated, i.e.; i) vertical and horizontal orientations of the cell stack, ii) U-shape and Z-shape flow patterns, and iii) upward and downward feeding directions. For these configurations, the velocity distributions across the stack were compared. The better flow distribution was observed for air with U-shape flow pattern and upward feeding. For fuel side, the flow with U-shape downward yields a relatively better flow distribution. Moreover, the results indicate that the effect of feeding direction is small in the stack with Z-shape flow. © The Electrochemical Society.
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Design of natural-rubber panel railroad crossing using finite element method
(2018-08-14)
Sukhom, Aunna
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Jangchud, Ittipol
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Pimsarn, Monsak
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Charoensuk, Jarruwat
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Treeporncharoen, Veerachai
Thailand has a railway system that is available throughout the country, so there are several railroad crossings. These crossings are generally made of concrete or logs with multiple constraints. There are some disadvantages of concrete railroad crossing, such as, crack, noise during car passing over. To overcome these disadvantages, the softer materials should be used instead. Therefore, this research proposes the natural rubber, widely grown throughout Thailand, panel railroad crossing. However, the natural rubber alone is not enough to withstand the harsh condition. Thus, it is necessary to have some addition ingredients that will enhance the natural rubber properties. The material used in this research is a rubber compound between Chloroprene Rubber (CR) 75% and Natural rubber (NR) 25% blend with additives such as carbon black (CB), magnesium oxide (MgO) and sulfur (S8). The objectives of this article were to analyze the deformation of the natural rubber panel railroad crossing and to evaluate its safety factor, defined as the ratio of strain at break and the maximum equivalent strain, using finite element method. In the analysis, the applied loading of the model was obtained from the State Railway of Thailand. The analyzed results reveal that the deflection of rubber panels passes the standard from State Railway of Thailand. Safety factor of external rubber panel is 27.03 and for internal rubber panels are 9.12 and 15.29. The metal pads had elastically deformed and concrete railroad sleeper deformation was very small.

Charoensuk, Jarruwat

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