http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Tanshen, M.R.,Lee, S.,Kim, J.,Kang, D.,Noh, J.,Chung, H.,Jeong, H. Springer Science and Business Media 2014 Journal of Central South University Vol.21 No.6
Effective thermal performance of oscillating heat pipe (OHP) is driven by inside pressure distribution. Heat transfer phenomena were reported in terms of pressure and frequency of pressure fluctuation in multi loop OHP charged with aqueous Al2O3 and MWCNTs/Al2O3 nanoparticles. The influences on thermal resistance of aqueous Al2O3, MWCNTs as well as the hybrid of them in OHP having 3 mm in inner diameter were investigated at 60% filling ratio. Experimental results show that thermal characteristics are significantly inter-related with pressure distribution and strongly depend upon the number of pressure fluctuations with time. Frequency of pressure depends upon the power input in evaporative section. A little inclusion of MWCNTs into aqueous Al2O3 at 60% filling ratio achieves the highest fluctuation frequency and the lowest thermal resistance at any evaporator power input though different nanofluids cause different thermal performances of OHPs.
Experimental Investigations on the Temperature Characteristics of Loop Heat Pipe
리야드(Md.Riyad Tanshen),이광성(Kwangsung Lee),정효민(HyoMin Jeong),정한식(Hanshik Chung) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11
Loop heat pipes (LHPs) are temperature tools having a mighty thermo-hydrodynamic coupling ruling the thermal performance. In this paper, heat pipe is experimentally studied thereby providing vital information on the parameter dependency of their thermal performance. The impact depiction has been done for the variation of tube model of the device. LHPs are constructed of copper capillary tubes of outer diameter 6.25 ㎜, inner diameter 4 ㎜ heated by constant temperature water bath cooled by ambient temperature. Using four type of LHPs of copper capillary tubes is length of 1500 ㎜ and 650㎜ inside tubes working fluid is R-22 Pressure 2 bar and mass 34g,32g,28g,16g. The results show an impact of four different types of (LHPs) used. These data collected using thermocouple and data logger connected with computer. The results indicate a strong influence of filling ratio on the performance.
진동열교환기에서 다양한 충진율에 따른 압력및 진동특성에 관한 연구
리야드(Md.Riyad Tanshen),김영식(Young-Sik Kim),이대철(Dae-chul Lee),정한식(Han-Shik Chung),정효민(Hyo-Min Jeong) 대한설비공학회 2011 대한설비공학회 학술발표대회논문집 Vol.2011 No.7
The article focuses on pressure characteristics inside single loop oscillating heat pipe (OHP) that is of 4.5 ㎜ inner diameter copper tube with the length of 440 ㎜. The system consists of evaporator, condenser and adiabatic section at middle of heat pipe. Distilled water is used as working fluid inside the OHP with different filling ratios of 40%, 60%, 80% of total volume. Experimental results shows that thermal characteristics are significantly inter-related with pressure fluctuations as well as pressure frequency. And the pressure frequency also depends upon the evaporator temperature which has been maintained from 60oC to 96oC. The Investigation shows 60% filling ratio gives the highest magnitude of inside pressure and highest pressure frequency at any of setting evaporator temperature. Piezoresistive absolute pressure sensor (Model-Kistler 4045A5) has been used to take data.
Munkhbayar, B.,Tanshen, Md.Riyad,Jeoun, Jinseong,Chung, Hanshik,Jeong, Hyomin Elsevier 2013 Ceramics international Vol.39 No.6
<P><B>Abstract</B></P> <P>This paper reports a significant enhancement in the thermal conductivity of silver-nanoparticle-based aqueous nanofluids with the addition of negligible amounts of multi-walled carbon nanotubes (MWCNTs). The present work was conducted using purified MWCNTs/water nanofluids prepared by a wet grinding method. Silver nanoparticles were dispersed into the MWCNT/water nanofluids via a one-step method using pulse power evaporation, which was observed to improve the dispersibility and thermal conductivity of the nanofluids. A particle sizing system (PSS) and transmission electron microscopy (TEM) were used to confirm the size of silver nanoparticles in base fluids. The PSS measurement results reveal that the size of the silver nanoparticles was approximately 100nm, which is in good agreement with the results obtained from TEM and SEM. The maximum absorbance (2.506abs at a wavelength of 264nm) and highest thermal conductivity enhancement (14.5% at 40°C) were achieved by a fluid containing ‘0.05wt% MWCNTs–3wt% Ag’ composite.</P>
Batmunkh, Munkhbayar,Tanshen, Md. R.,Nine, Md. J.,Myekhlai, Munkhshur,Choi, Heekyu,Chung, Hanshik,Jeong, Hyomin American Chemical Society 2014 INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH - Vol.53 No.20
<P>Nanofluid is a colloidal suspension which has received great attention over the past two decades, but its limited heat transfer enhancement is a matter of concern for industrial applications. We demonstrate an improvement in the thermal conductivity of TiO<SUB>2</SUB> nanofluids with an addition of negligible amounts of modified silver “Ag” nanoparticles. In this work, the surface/shape of newly synthesized “Ag” nanoparticles is modified by planetary ball milling. Then, to enhance the thermal conductivity of TiO<SUB>2</SUB> nanofluids, the flattened “Ag” particles are incorporated with the combination of small (15 nm) and large (300 nm) TiO<SUB>2</SUB> nanoparticles in an aqueous solution. The thermal conductivities of Ag/TiO<SUB>2</SUB>–water nanofluids with various weight concentrations are measured at temperatures ranging from 15 to 40 °C. As a result, the present study confirms that the thermal conductivity of TiO<SUB>2</SUB> based solution can be improved by introducing the flattened “Ag” particles.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/iecred/2014/iecred.2014.53.issue-20/ie403712f/production/images/medium/ie-2013-03712f_0006.gif'></P>
Study on the heat transfer properties of raw and ground graphene coating on the copper plate
Sin-il Lee,Md. R. Tanshen,Kwang-sung Lee,Myekhlai Munkhshur,Hyo-min Jeong,Han-shik Chung 한국동력기계공학회 2013 동력시스템공학회지 Vol.17 No.5
A high thermal conductivity material, namely graphene is treated by planetary ball milling machine to transport the heat by increasing the temperature. Experiments were performed to assess the heat transfer enhancement benefits of coating the bottom wall of copper substrate with graphene. It is well known that the graphene is unable to disperse into base fluid without any treatment, which is due to the several reasons such as attachment of hydrophobic surface, agglomeration and impurity. To further improve the dispersibility and thermal characteristics, planetary ball milling approach is used to grind the raw samples at optimized condition. The results are examined by transmission electron microscopy, x-ray diffraction, Raman spectrometer, UV-spectrometer, thermal conductivity and thermal imager. Thermal conductivity measurements of structures are taken to support the explanation of heat transfer properties of different samples. As a result, it is found that the planetary ball milling approach is effective for improvement of both the dispersion and heat carriers of carbon based material. Indeed, the heat transfer of the ground graphene coated substrate was higher than that of the copper substrate with raw graphene.
신용한(Y. H. Shin),리야드(Md. Riyad Tanshen),정한식(H. C. Chung),정효민(H. M. Jeong) 한국동력기계공학회 2012 동력시스템공학회지 Vol.16 No.2
The geothermal energy is one of the renewable energy sources which can contribute in accomplishing a vision and goal of the national plan on energy for a government suggestion. Especially, the geothermal energy is evaluated as the nearly unlimited resources. The yearly underground temperature distribution by depth is very important to the design of air-conditioning system which uses a geothermal energy. Furthermore, there has no data for comparisons to numerical analysis. In this study, the yearly underground temperature is measured under the depth of 2 m in Tongyeong, and these data are compared with numerical analysis results for checking the accuracy. The results showed that the experimental temperature and numerical results had a good agreements and these results will be utilized to predict a performance of air-conditioning system for using a geothermal energy.
Is metal nanofluid reliable as heat carrier?
Nine, Md.J.,Chung, H.,Tanshen, Md.R.,Osman, N.A.B.A.,Jeong, H. Elsevier Scientific Pub. Co 2014 Journal of hazardous materials Vol.273 No.-
A pre- and post experimental analysis of copper-water and silver-water nanofluids are conducted to investigate minimal changes in quality of nanofluids before and after an effective heat transfer. A single loop oscillating heat pipe (OHP) having inner diameter of 2.4mm is charged with aforementioned nanofluids at 60% filling ratio for end to end heat transfer. Post experimental analysis of both nanofluids raises questions to the physical, chemical and thermal stability of such suspension for hazardless uses in the field of heat transfer. The color, deposition, dispersibility, propensity to be oxidized, disintegration, agglomeration and thermal conductivity of metal nanofluids are found to be strictly affected by heat transfer process and vice versa. Such degradation in quality of basic properties of metal nanofluids implies its challenges in practical application even for short-term heat transfer operations at oxidative environment as nano-sized metal particles are chemically more unstable than its bulk material. The use of the solid/liquid suspension containing metal nanoparticles in any heat exchanger as heat carrier might be detrimental to the whole system.
Tae-Jin Lee,Myekhlai Munkhshur,Md. Riyad Tanshen,Dae-Chul Lee,Han-Shik Chung,Hyo-Min Jeong 한국동력기계공학회 2013 동력시스템공학회지 Vol.17 No.5
The activation process is the key to graphene’s practical application. In this study, the effect of grinding speed in planetary ball mill on structural integrity of graphene has been studied at various grinding speed such as 100 rpm, 200 rpm, 300 rpm, 400 rpm and 500 rpm. The morphology and structure of pristine graphene and ground graphenes were studied using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X.ray diffraction (XRD) and Raman spectroscopy respectively. According to these results, structural properties of graphene were improved when grinding speed was increased.