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Uruno, Yumi,Choi, Geunwon,Sung, Minjun,Chung, Jaewon,Kim, Hyojun,Lee, Kihyun Elsevier 2019 Applied Thermal Engineering Vol.150 No.-
<P><B>Abstract</B></P> <P>In an attemperator, spray water is injected into superheated steam to control its temperature. Since the temperature measured by the thermowell installed at the attemperator outlet is used for the feedback control of the spray water, it is important that the spray water is completely evaporated before the thermowell. This ensures that the thermowell measures the temperature of desuperheated steam.</P> <P>In this study, measurements from the commissioning test of a coal-fired steam power plant were analyzed using transient analyses. These analyses compensated for delayed temperature measurement at thermowells with large heat capacities and the temperature change of spray water extracted far from the attemperator. By using these results for the enthalpy balance in the attemperator, the spray water flow could be calculated accurately enough to verify whether the spray-injected steam was completely desuperheated before the outlet thermowell or not, even during operations with changing the generator load. Temperature readings from thermowells depend on the subcritical and supercritical conditions and the validity of the various simplifications used in the transient analysis were discussed. According to the transient analysis of the commissioning data, the thermowell distance in one of the attemperators could be judged as being too short to ensure complete desuperheating of the spray-injected steam, and thus, this should be considered in the control logic.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Control logic for spray water uses thermowell measurements at attemperator outlet. </LI> <LI> Thus, spray injected steam should be desuperheated before the outlet thermowell. </LI> <LI> Enthalpy balance in the attemperator using steady-state analysis is not accurate. </LI> <LI> A transient analysis methodology using a lumped capacitance model is presented. </LI> <LI> Commissioning data of the attemperator in the steam power plant was analyzed. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Cho, Baekhyun,Choi, Geunwon,Uruno, Yumi,Kim, Hyunseo,Chung, Jaewon,Kim, Hyojun,Lee, Kihyun Elsevier 2017 Applied Thermal Engineering Vol.113 No.-
<P><B>Abstract</B></P> <P>An attemperator is a device that is used to spray water into the superheated steam between the primary, platen, and final superheaters and the reheat lines. The goal of the attemperator is to control the temperature of the superheated steam in accordance with desired turbine-inlet temperature during both steady-state and transient operation. Because the thermowell installed at the attemperator outlet is tied back to the feedback control of the spray water, the spray water should evaporate ahead of the thermowell for accurate control of the steam temperature. In this work, the completion of the evaporation ahead of the thermowell was analyzed using the enthalpy balance from the start-up commissioning data of an 800-MW coal-fired steam power plant. In addition, the phenomena of the spray atomization and its concurrent evaporation in an attemperator were physically modeled, and a simple one-dimensional simulation was conducted to verify the analysis of the commissioning data.</P> <P><B>Highlights</B></P> <P> <UL> <LI> An attemperator is a device to spray water into the superheated steam. </LI> <LI> The evaporation was analyzed using the enthalpy balance from the commissioning data. </LI> <LI> The spray atomization and its concurrent evaporation in an attemperator were physically modeled. </LI> <LI> A simple one-dimensional simulation was conducted to verify the commissioning results. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Review : PPARγ Agonist Beyond Glucose Lowering Effect
( Akira Sugawara ),( Akira Uruno ),( Masataka Kudo ),( Ken Matsuda ),( Chul Woo Yang ),( Sadayoshi Ito ) 대한내과학회 2011 The Korean Journal of Internal Medicine Vol.26 No.1
The nuclear hormone receptor PPARγ is activated by several agonists, including members of the thiazolidinedione group of insulin sensitizers. Pleiotropic beneficial effects of these agonists, independent of their blood glucose- lowering effects, have recently been demonstrated in the vasculature. PPARγ agonists have been shown to lower blood pressure in animals and humans, perhaps by suppressing the renin-angiotensin (Ang)-aldosterone system (RAAS), including the inhibition of Ang II type 1 receptor expression, Ang-II-mediated signaling pathways, and Ang-II-induced adrenal aldosterone synthesis/secretion. PPARγ agonists also inhibit the progression of atherosclerosis in animals and humans, possibly through a pathway involving the suppression of RAAS and the thromboxane A2 system, as well as the protection of endothelial function. Moreover, PPARγ-agonist-mediated renal protection, especially the reduction of albuminuria, has been observed in diabetic nephropathy, including animal models of the disease, and in non-diabetic renal dysfunction. The renal protective activities may reflect, at least in part, the ability of PPARγ agonists to lower blood pressure, protect endothelial function, and cause vasodilation of the glomerular efferent arterioles. Additionally, anti-neoplastic effects of PPARγ agonists have recently been described. Based on the multiple therapeutic actions of PPARγ agonists, they will no doubt lead to novel approaches in the treatment of lifestyle-related and other diseases. (Korean J Intern Med 2011;26:19-24)
분사제트 온도변화에 따른 벽면충돌 현상에 대한 실험적 연구
최현훈(Hyeonhun Choi),우루노유미(Yumi Uruno),김상호(Sangho Kim),정재원(Jaewon Chung) 대한기계학회 2018 대한기계학회 춘추학술대회 Vol.2018 No.12
In order to remove dissolved oxygen and carbon dioxide from feedwater in power generation facilities, boilers and incinerators, deaerators are essential. In actual deaerator, temperature of spray is about 145°C and the surrounding temperature is about 177°C (steam temperature). It is necessary to analyze the temperature in order to improve the efficiency of deaerator. In this paper, splashed fraction and jet breakup according to the distance from nozzle were studied. Also, Liquid film shapes on the vertical wall are visualized and analyzed using highspeed camera. These were obtained at different temperature respectively. As temperature increases, ξ(splashed fraction) becomes smaller overall. Also, the value of ξ<SUB>max</SUB>(maximum of splashed fraction) decreases as the temperature increases. The Rayleigh regime, the first wind-induced regime, and the second wind-induced regime were confirmed by jet breakup images. The phenomenon that <SUB>max</SUB> decreased with increasing temperature was visualized and confirmed. It was confirmed that the diameter of the liquid film becomes larger as the temperature rises. That is, ξ decreases because droplets spread on the wall and the thickness of the liquid film becomes thinner. Therefore, when the temperature of water rises, ξ decreases. The results of this paper are used to increase the efficiency of actual deaerator and provide data for design and optimization.