Radiant syngas cooler (RSC) is the key heat recovery equipment in coal gasification system. The syngas from gasifier carries large amount of slags in which the mass fraction of fly ash less than 100 μm is about 20%. ...Radiant syngas cooler (RSC) is the key heat recovery equipment in coal gasification system. The syngas from gasifier carries large amount of slags in which the mass fraction of fly ash less than 100 μm is about 20%. Studying the optical properties of fly ash has high significance for the optimization of heat transfer calculation in RSC. A new experimental method was proposed to inversely calculate the radiative parameters of particles—“KBr transmittance-reflectance method”. By measuring the “directional-hemispherical” reflectance and transmittance of fly ash particles by FTIR under the wavelength range of 0.55 - 1.65 μm, using the four-flux model to solve the radiative transfer equation and combing with Mie theory, the absorption and scattering efficiency of 22.7 μm fly ash and optical constant (also known as complex refractive index, m = n + ik) of fly ash were inversely calculated. The results indicated that for fly ash with large size parameter, there was no obvious change of the absorption and scattering efficiency when the mass fraction of Fe2O3 was between 5.65% and 16.53%, which was well explained by Mie theory;The obtained optical constant was close to the results of KBr trans-mittance method.展开更多
An evaluation of the urban park vegetation was conducted by integrating airborne multispectral scanning system ( MSS ) thermal band data with meteorological. MSS data acquired in the morning and afternoon were u...An evaluation of the urban park vegetation was conducted by integrating airborne multispectral scanning system ( MSS ) thermal band data with meteorological. MSS data acquired in the morning and afternoon were utilized to assess the radiant energy budget of different ground cover types and its relationship with the surface types. The spatial distribution of surface temperature ( Ts ) and surface albedo ( A ) varied between different surfaces. However, the spatial variability of net radiation ( Rn ) was reduced by negative feedback of A Ts relationship. The Normalized Difference Vegetation Index ( NDVI ) had a negative correlation with Ts but positively correlated to Rn of the different surface types. Thermal response number ( TRN ), which expresses the dissipative behavior of radiant energy, correctly characterized each ground cover type according to the validated surface property. Forested and lawn covered sites had the highest TRN values consistent with their tendency to resist microclimatic change. The approach shows that by utilizing the MSS thermal signatures, we can relate the microenvironment processes to the biophysical character of each site offering an opportunity to diagnose site specific problems. The approach is proposed as a direct and easily adaptable method for monitoring the urban green park areas and for making objective decisions about their management.展开更多
文摘Radiant syngas cooler (RSC) is the key heat recovery equipment in coal gasification system. The syngas from gasifier carries large amount of slags in which the mass fraction of fly ash less than 100 μm is about 20%. Studying the optical properties of fly ash has high significance for the optimization of heat transfer calculation in RSC. A new experimental method was proposed to inversely calculate the radiative parameters of particles—“KBr transmittance-reflectance method”. By measuring the “directional-hemispherical” reflectance and transmittance of fly ash particles by FTIR under the wavelength range of 0.55 - 1.65 μm, using the four-flux model to solve the radiative transfer equation and combing with Mie theory, the absorption and scattering efficiency of 22.7 μm fly ash and optical constant (also known as complex refractive index, m = n + ik) of fly ash were inversely calculated. The results indicated that for fly ash with large size parameter, there was no obvious change of the absorption and scattering efficiency when the mass fraction of Fe2O3 was between 5.65% and 16.53%, which was well explained by Mie theory;The obtained optical constant was close to the results of KBr trans-mittance method.
文摘An evaluation of the urban park vegetation was conducted by integrating airborne multispectral scanning system ( MSS ) thermal band data with meteorological. MSS data acquired in the morning and afternoon were utilized to assess the radiant energy budget of different ground cover types and its relationship with the surface types. The spatial distribution of surface temperature ( Ts ) and surface albedo ( A ) varied between different surfaces. However, the spatial variability of net radiation ( Rn ) was reduced by negative feedback of A Ts relationship. The Normalized Difference Vegetation Index ( NDVI ) had a negative correlation with Ts but positively correlated to Rn of the different surface types. Thermal response number ( TRN ), which expresses the dissipative behavior of radiant energy, correctly characterized each ground cover type according to the validated surface property. Forested and lawn covered sites had the highest TRN values consistent with their tendency to resist microclimatic change. The approach shows that by utilizing the MSS thermal signatures, we can relate the microenvironment processes to the biophysical character of each site offering an opportunity to diagnose site specific problems. The approach is proposed as a direct and easily adaptable method for monitoring the urban green park areas and for making objective decisions about their management.
