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터빈 블레이드 후연부 사다리꼴 채널 내 내부 축소 홀 설치에 따른 열전달 특성
허정훈(Jeonghun Heo),김태현(Taehyun Kim),박희승(Hee Seung Park),송호섭(Ho Seop Song),이창용(Changyong Lee),조형희(Hyung Hee Cho) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.11
The gas turbine has been a widely used engine system in aircraft and powerplants. Due to the high turbine inlet temperature, diverse turbine cooling techniques have been developed. In this study, the trailing edge trapezoidal channel is designed, and the 45 degrees of rib turbulators and inner hole are also installed. The naphthalene sublimation experiment is conducted to analyze heat transfer characteristics. As a result of the experiment, heat transfer is higher when the inner hole is installed. Also, the heat transfer of the mid-hole case was higher than the inlet hole case, so the heat transfer increment by the jet effect is confirmed. Therefore, it can be considered to install the inner hole in the trailing edge channel.
Nanoarchitecture of MOF-derived nanoporous functional composites for hybrid supercapacitors
Kim, Jeonghun,Young, Christine,Lee, Jaewoo,Heo, Yoon-Uk,Park, Min-Sik,Hossain, Md. Shahriar A.,Yamauchi, Yusuke,Kim, Jung Ho The Royal Society of Chemistry 2017 Journal of materials chemistry. A, Materials for e Vol.5 No.29
<▼1><P>A new nanoarchitecture approach based on metal–organic frameworks (MOFs) is reported that can achieve high electrochemical energy storage <I>via</I> utilizing both electric double-layer supercapacitive and pseudocapacitive properties within a single nanoporous composite particle.</P></▼1><▼2><P>A new nanoarchitecture approach based on metal–organic frameworks (MOF) is reported that can achieve high electrochemical energy storage <I>via</I> utilizing both electric double-layer supercapacitive and pseudocapacitive properties within a single nanoporous composite particle. Herein, a predesigned Co<SUP>2+</SUP>-excess bimetallic hybrid Co/Zn zeolitic imidazole framework was used to fabricate a composite containing N-doped nanoporous carbon with a rich carbon nanotube (CNT) content on particle surfaces without H2, with the carbon coexisting with Co nanoparticles (NPs) and Co3O4, through controlled carbonization at 800 °C and subsequent oxidation at 250–300 °C. Optimized nanoporous carbon composites were obtained by tracking the formation of Co3O4 and destruction of N-doped nanoporous carbon (NPC) <I>via</I> detailed X-ray diffraction and X-ray photoelectron spectroscopy analysis. The resulting material showed a high surface area of ∼202 m<SUP>2</SUP> g<SUP>−1</SUP> and included coexisting micro- and mesoporous N-doped carbon, CNTs, Co NPs, and Co3O4 (15 nm in size) after a thermal oxidation process in air at 250 °C for 5 h. Surprisingly, the as-prepared MOF-derived nanoarchitecture exhibited superior electrochemical storage performance, with a capacitance of 545 F g<SUP>−1</SUP> within a wide potential window, achieving up to 320% enhanced capacitance compared to that of pristine nanoporous carbon, which is higher than those of most MOF-derived carbons reported so far. Our strategic nanoarchitecture design for MOFs offers a new opportunity for future applications in high performance energy storage systems.</P></▼2>