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

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

Fractal analysis for heat extraction in geothermal system

Heat conduction and convection play a key role in geothermal development. These two processes are coupled and influenced by fluid seepage in hot porous rock. A number of integer dimension thermal fluid models have been proposed to describe this coupling mechanism. However, fluid flow, heat conduction and convection in porous rock are usually non-linear, tortuous and fractal, thus the integer dimension thermal fluid flow models can not well describe these phenomena. In this study, a fractal thermal fluid coupling model is proposed to describe the heat conduction and flow behaviors in fractal hot porous rock in terms of local fractional time and space derivatives. This coupling equation is analytically solved through the fractal travelling wave transformation method. Analytical solutions of Darcy?s velocity, fluid temperature with fractal time and space are obtained. The solutions show that the introduction of fractional parameters is essential to describe the mechanism of heat conduction and convection.

Heat and mass transfer in wood composite panels during hot pressing: Part 3. Predicted variations and interactions of the pressing variables

As a continuation of previous publications on a physical-mathematical model of heat and mass transfer and a structural model of mat permeability, this paper presents typical prediction results for 15 pressing variables for strand mats. A case study and complete solutions to the governing equations are provided. The results show how the heat and mass transfer is controlled by heat conduction and convection involving gas flow and phase change. The model predictions provide a comprehensive illustration of the temporal and spatial variations of basic pressing variables, including mat temperature, gas pressure, moisture control and resin curing rate. The model offers a powerful tool for simulating the effects of mat structure, pressing schedule and initial mat conditions.