scholarly journals Hybrid cylinder dryer for the drying of sheet-form materials with hot air

2018 ◽  
Author(s):  
Sung Il Kim ◽  
Sang Hyun Oh ◽  
Won Pyo Chun ◽  
Ki Ho Park ◽  
Byoung Hyuk Yu
Keyword(s):  
Heat Transfer ◽  
Energy Efficiency ◽  
Heat Conduction ◽  
Energy Efficient ◽  
Convection Heat Transfer ◽  
Convection Heat ◽  
Compact Structure ◽  
Heating Method ◽  
Hot Air ◽  
Heat Conduction And Convection

In this paper, we introduce a novel energy-efficient dryer that uses hot air as a combined heating method of heat conduction and convection heat transfer. The dryer consisting of rotary cylinders and arched jackets is structurally different from conventional dryers. We designed and built a hybrid 4-cylinder dryer for sheet-form materials. The energy consumption to evaporate unit water is about 930 kcal/kg moisture from the experimental results of a hybrid 4-cylinder dryer. The hybrid 4-cylinders dryer has a compact structure with about 1/3 of the size of a conventional dryer for the drying of sheet-form materials. Keywords: Dryer; Hot Air; Sheet-form; Energy Efficiency; Hybrid

Effect of Wall Heat Conduction on Natural Convection Heat Transfer in a Square Enclosure

1985 ◽  
Vol 107 (1) ◽  
pp. 139-146 ◽  
Author(s):  
D. M. Kim ◽  
R. Viskanta
Keyword(s):  
Heat Transfer ◽  
Heat Conduction ◽  
Natural Convection ◽  
Solid Wall ◽  
Convection Heat Transfer ◽  
Natural Convection Heat Transfer ◽  
Convection Heat ◽  
Square Enclosure ◽  
Void Fractions ◽  
Aspect Ratios

This paper presents numerical and experimental results for buoyancy-induced flow in a two-dimensional, fluid-filled enclosure. Rectangular cavities formed by finite conductance walls of different void fractions and aspect ratios are considered. Parametric heat transfer calculations have been performed and results are presented and discussed. Local and average Nusselt numbers along the cavity walls are reported for a range of parameters of physical interest. The temperatures in the walls were measured with thermocouples, and the temperature distributions in the air-filled cavity were determined using a Mach-Zehnder interferometer. Good agreement has been obtained between the measured and the predicted temperatures in both the solid wall and in the fluid using the mathematical model. Wall heat conduction reduces the average temperature differences across the cavity, partially stabilizes the flow, and decreases natural convection heat transfer.

Analyses of Flow Field and Heat Exchange about Limestone Grain in the Preheater

2014 ◽  
Vol 915-916 ◽  
pp. 974-977
Author(s):  
Yong Gang Liu ◽  
Xiao Yang Zhang ◽  
Jing Yang Zheng ◽  
Jin Fa Xie
Keyword(s):  
Heat Transfer ◽  
Finite Element ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Convection Heat Transfer ◽  
Particle Model ◽  
Convection Heat ◽  
Convection Heat Transfer Coefficient ◽  
Hot Air ◽  
Heat Transfer Theory

According to the structural features of the vertical preheater, the 2-dimention finite element models are set up for the section of the preheater with different arrangement and diameters for the limestone grains. The situation of gas-solid two-phase flow between the limestone grains and the hot air in the preheater is simulated by the discrete particle model. Based on the heat transfer theory, the convection heat transfer coefficient between the limestone grains and the hot air is deduced by means of the experimental correlation of the air cross-flow tube bundles. On the simulation of the 2-dimention finite element model of the vertical preheater based on the FLOTRAN module of ANSYS, the temperature field, pressure field and velocity field of the limestone grains are obtained. The results show that there is a little change of convection heat transfer coefficient by varying the arrangement of limestone grains. The convection heat transfer coefficient is improved by employing the limestone grains with little diameter. The larger the gap between the grains is, the larger the convection heat transfer coefficient is.

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