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Jae Cheol Lee

Bio: Jae Cheol Lee is an academic researcher from Korea University. The author has contributed to research in topics: Mass transfer & Bubble. The author has an hindex of 3, co-authored 9 publications receiving 103 citations.

Papers
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Journal ArticleDOI
Ki Bong Lee1, Byung Hee Chun1, Jae Cheol Lee1, Chan Ho Lee1, Sung Hyun Kim1 
TL;DR: In this paper, an experimental analysis of ammonia-water absorption in a plate-type absorber was performed in the bubble mode and the results were converted into dimensionless numbers to elucidate physical phenomena and plotted as Sherwood number versus Reynolds number for mass transfer performance.

47 citations

Journal ArticleDOI
TL;DR: In this paper, both the numerical and experimental analyses in the absorption process of a bubble mode absorber were performed, where gas was injected into the bottom of the absorber at a constant solution flow rate.
Abstract: An absorber is a major component in the absorption refrigeration systems, and its performance greatly affects the overall system performance. In this study, both the numerical and experimental analyses in the absorption process of a bubble mode absorber were performed. Gas was injected into the bottom of the absorber at a constant solution flow rate. The region of gas absorption was estimated by both numerical and experimental analyses. A higher gas flow rate increases the region of gas absorption. As the temperature and concentration of the input solution decrease, the region of gas absorption decreases. In addition, the absorption performance of the countercurrent flow was superior to that of cocurrent. Mathematical modeling equations were derived from the material balance for the gas and liquid phases based on neglecting the heat and mass transfer of water from liquid to gas phase. A comparison of the model simulation and experimental results shows similar values. This means that this numerical model can be applied for design of a bubble mode absorber.

35 citations

Journal ArticleDOI
TL;DR: In this paper, an experimental analysis of ammonia-water absorption process was performed for the falling film and bubble modes in a plate-type absorber, and the experiments were made to examine the effects of solution flow rate and gas flow rate on the performance of the absorber.
Abstract: An experimental analysis of ammonia-water absorption process was performed for the falling film and bubble modes in a plate-type absorber. The experiments were made to examine the effects of solution flow rate and gas flow rate on the performance of the absorber. It was found that the bubble mode is superior to the falling film mode for mass transfer performance, and more heat was generated in the bubble mode. Increase of solution flow rate rarely affected the mass transfer, but improved the heat transfer. As the gas flow rate increased, fluidization occurred in the bubble mode and influenced the thermal boundary layer. However, channeling appeared in the falling film mode and decreased the heat transfer area. Increase of the gas flow rate greatly enhanced the performance of heat transfer in the bubble mode but made it worse in the falling film mode. Finally, the results were converted into dimensionless numbers to elucidate physical phenomena and we plotted Sherwood number versus Reynolds number for mass...

22 citations

Journal ArticleDOI
Ki Bong Lee1, Byung Hee Chun1, Jae Cheol Lee1, Chan Jin Park1, Sung Hyun Kim1 
TL;DR: In this article, a cylindrical tube absorber was used for the bubble mode and characteristics such as concentration, temperature, and pressure were measured and they reflected the condition of the absorber well.
Abstract: Experimental analysis was performed in a cylindrical tube absorber which is considered to be suitable for the bubble mode. Characteristics such as concentration, temperature, and pressure were measured and they reflected the condition of absorber well. The variation of characteristics was conspicuous near the inlet region of the ammonia gas. The ammonia gas and the solution flowed cocurrently and countercurrently and the results were compared.

3 citations

Journal ArticleDOI
TL;DR: In this paper, an interactive scale bridge of data exchange is proposed to aid the multiscale modeling and dynamic simulation of combined cycle (CC) power plant integration with two-tank thermal energy storage (TES) system using gPROMS and SimCentral.
Abstract: With different computational tools, simulations ranging from detailed and rigorous mathematical models to overall process plant of black box models can be carried out. Whereas most of these computational tools cannot practically execute different scales of models at the same time, it becomes relevant to devise strategies in coupling two or more of them for better analysis of processes. In this light, this study proposes Excel as an interactive scale bridge of data exchange to aid the multiscale modeling and dynamic simulation of combined cycle (CC) power plant integration with two-tank thermal energy storage (TES) system using gPROMS and SimCentral. This is relevant to analyze not only the performance of TES, but the feasibility of its integration with CC in augmenting energy production to meet daily power demand. The integrated system modeled in four operational modes of CC increased in power generation by 7.3 MW at an efficiency of 98.30%. The study validated the usefulness of the TES integration of 99.66% efficiency. The research results provide a communication strategy for different computational tools and an approach to effectively increase CC power production to meet varying daily demand.

3 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper, the authors used ammonia water as the working fluid to look at how absorption takes place in a plate heat exchanger operating under typical conditions of absorption chillers, driven by low temperature heat sources.

73 citations

Journal ArticleDOI
TL;DR: In this article, a vertical plate heat exchanger is used to transfer boiling heat and the associated frictional pressure drop of a mixture of ammonia/water mixture flowing in a vertical stack heat exchange is investigated.
Abstract: The objective of this work is to contribute to the development of plate heat exchangers as desorbers for ammonia/water absorption refrigeration machines driven by waste heat or solar energy. In this study, saturated flow boiling heat transfer and the associated frictional pressure drop of ammonia/water mixture flowing in a vertical plate heat exchanger is experimentally investigated. Experimental data is presented to show the effects of heat flux between 20 and 50 kW m−2, mass flux between 70 and 140 kg m−2 s−1, mean vapour quality from 0.0 to 0.22 and pressure between 7 and 15 bar, for ammonia concentration between 0.42 and 0.62. The results show that for the selected operating conditions, the boiling heat transfer coefficient is highly dependent on the mass flux, whereas the influence of heat flux and pressure are negligible mainly at higher vapour qualities. The pressure drop increases with increasing mass flux and quality. However, the pressure drop is independent of the imposed heat flux.

70 citations

Journal ArticleDOI
TL;DR: In this paper, an extensive review of heat and mass transfer correlations in the framework of sorption machines operating based on the falling film technology, in which ammonia-water and lithium bromide-water are used as the working fluid pairs.

62 citations

Journal ArticleDOI
TL;DR: In this article, the authors presented a detailed analysis of the heat and mass transfer processes during the absorption of ammonia into water in a co-current vertical tubular absorber, where the absorption process progresses as the vapour and liquid contact inside the tubes.

54 citations

Journal ArticleDOI
TL;DR: In this article, the experimental data of Taboas et al. (2010) on flow boiling of ammonia/water in a plate heat exchanger are compared with the predicted values using the correlations available in the open literature for the boiling heat transfer coefficient and pressure drop.
Abstract: Plate heat exchangers are gaining acceptance in absorption refrigeration systems due to their high transfer rates, compactness, and low refrigerant charge. Nevertheless, boiling heat transfer and pressure drop studies with mixtures in plate heat exchangers (PHEs) are scarce. In this study, the experimental data of Taboas et al. (2010) on flow boiling of ammonia/water in a plate heat exchanger are compared with the predicted values using the correlations available in the open literature for the boiling heat transfer coefficient and pressure drop. In addition, this study proposes a new correlation based on a separate model by which to obtain the boiling coefficient. The new correlation uses a transition criterion, divided into an apparent nucleate boiling region where pure convective boiling cannot appear, and a region with competition between convective and apparent nucleate boiling. The correlation proposed can predict 98% of data from Taboas et al. (2010) within 20% error.

54 citations