Effect of gas inlet parameters on exergy transfer performance of sinter cooling process in vertical moving bed

2019 ◽  
Vol 152 ◽  
pp. 126-134 ◽  
Author(s):  
Junsheng Feng ◽  
Sheng Zhang ◽  
Hui Dong ◽  
Gang Pei
2011 ◽  
Vol 130-134 ◽  
pp. 1306-1309
Author(s):  
Jun Lan Yang ◽  
Yi Tai Ma ◽  
Min Xia Li

s: The obvious characteristics of transcritical CO2 cycle are that the heat rejection process takes place in the supercritical region (about 8-12Mpa). The heat transfer features of CO2 under supercritical pressure are different from those of the conventional refrigerants. And the heat transfer performances comparison study for supercritical CO2 fluid and the conventional refrigerants are carried out by means of thermo-physical properties analog analysis and experimental results quantitative comparison. The special properties variation of supercritical CO2 fluid makes its heat transfer performance different from the conventional fluids. From the view of properties analysis and quantitative comparison, the heat transfer performance of supercritical CO2 is equivalent to the condensation heat transfer of conventional refrigerants. Although the condensation coefficient is very large since there is phase change and latent heat variation in the condensation process, there is liquid film thermal resistance. While in the supercritical CO2 cooling process, there is no liquid film in existence and the thickness of the boundary layer is very thin. The heat transfer temperature difference is very large, so the heat transfer performance in the supercritical CO2 cooling process is equivalent to that of the condensation heat transfer.


Author(s):  
Shuang-Ying Wu ◽  
Yan Chen ◽  
You-Rong Li ◽  
Wen-Zhi Cui ◽  
Liao Quan

Based on the exergy transfer performance analysis of forced convective heat transfer through a tube with constant heat flux/ constant wall temperature for thermally and hydrodynamic fully developed turbulent flow, extended performance evaluation criteria for enhanced heat transfer surfaces based on the exergy transfer theorem have been developed. An exergy transfer performance evaluation criterion ΔNue or ΔE, which is defined as the difference of exergy-transfer Nusselt number or exergy transfer rate before and after enhanced heat transfer, is put forward. By reference to spirally grooved tube, the effect of Reynolds number, structure parameters of tube, dimensionless wall temperature difference and heat flux on the exergy transfer process is discussed. The results show that the exergy transfer performance of enhanced heat transfer with constant wall temperature is quite different from that with constant wall heat flux. An effective approach for exergy transfer performance evaluation and the optimal process parameters and configuration choice of enhanced heat transfer tube are provided.


Author(s):  
P. Echlin ◽  
M. McKoon ◽  
E.S. Taylor ◽  
C.E. Thomas ◽  
K.L. Maloney ◽  
...  

Although sections of frozen salt solutions have been used as standards for x-ray microanalysis, such solutions are less useful when analysed in the bulk form. They are poor thermal and electrical conductors and severe phase separation occurs during the cooling process. Following a suggestion by Whitecross et al we have made up a series of salt solutions containing a small amount of graphite to improve the sample conductivity. In addition, we have incorporated a polymer to ensure the formation of microcrystalline ice and a consequent homogenity of salt dispersion within the frozen matrix. The mixtures have been used to standardize the analytical procedures applied to frozen hydrated bulk specimens based on the peak/background analytical method and to measure the absolute concentration of elements in developing roots.


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