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과열증기처리 반탄화목분을 이용한 나무연탄 개발 및 혼합비에 따른 연료특성에 관한 연구
강찬영(Chanyoung Kang),유승민(Seungmin Yoo),강석구(Seoggoo Kang) 한국가구학회 2018 한국가구학회지 Vol.29 No.4
This study was carried out to develop wood briquettes by torrefied oak wood chips and anthracite coal by mixing ratio. For this purpose, the oak wood chips were torrefied at 300°C with the superheated steam and then mixed with wood powder, anthracite coal and gelatin binder by mixing ratio And then physical, thermal, fuel and microscope characteristics of the briquettes were analyzed. As the physical characteristics, the compression ratio of wood briquettes was higher than that of conventional briquettes. As the thermal properties, the higher the content of torrefied powder, the higher the calorific value but the lower the ash content. As a result of combustion test, 100% Torrefied wood briquette monoxide emission amount by mixing ratio was about 55% lower than conventional briquettes. Also, It was found that the shorter the combustion duration, the higher the content of torrefied powder. As a result of SEM observation, It can be found that the torrefied powder and the anthracite coal powder are physically. chemically bonded to each other due to the adhesion of gelatine. In conclusion, wood briquettes have a high initial temperature rise as the content of torrefied wood powder is high, but burnning time is shortter, so it is considered to be suitable for the case where it is necessary to heat up quickly or to use energy-consuming equipment in a short time.
Numerical Investigation on the Characteristics of Flow-Induced Noise in a Centrifugal Blower
Lee, Chanyoung,Jeong, Taebin,Ha, Kyoung-Ku,Kang, Shin-Hyoung Korean Society for Fluid machinery 2014 International journal of fluid machinery and syste Vol.7 No.1
In the present study, a computational analysis of the flow in a centrifugal blower is carried out to predict a performance and to explain noise characteristics of the blower. Unsteady, 3D Navier-Stokes equations were solved with k-${\varepsilon}$ turbulence model using CFX software. CFD results were compared with the experimental data that is acquired from an experiment conducted with the same blower. The pressure fluctuation in the blower was transformed into the frequency domain by Fourier decomposition to find the relationship between flow behaviors and noise characteristics. Sound pressure level (SPL) which is obtained from wall pressure fluctuation at impeller outlet represents relative overall sound level of the blower well. Sound spectra show that there are some specific peak frequencies at each mass flow rate and it can be explained by flow pattern.