Calculation of the temperature of boundary layer beside wall with time-dependent heat transfer coefficient

Abstract

This paper proposes to investigate the changes in the temperature of external wall boundary layers of buildings when the heat transfer coefficient reaches its stationary state in time exponentially. We seek the solution to the one-dimensional parabolic partial differential equation describing the heat transfer process under special boundary conditions. The search for the solution originates from the solution of a Volterra integral equation of the second kind. The kernel of the Volterra integral equation is slightly singular therefore its solution is calculated numerically by one of the most efficient collocation methods. Using the Euler approach an iterative calculation algorithm is obtained, to be implemented through a programme written in the Maple computer algebra system. Changes in the temperature of the external boundary of brick walls and walls insulated with polystyrene foam are calculated. The conclusion is reached that the external temperature of the insulated wall matches the air temperature sooner than that of the brick wall.

Aerodynamics and Heat Transfer over Solid-Deflectors in Transverse, Staggered, Corrugated-Upstream and Corrugated-Downstream Patterns

“…The outlet temperature of air was compared with experimental results and there was a good agreement in between them. Other works can be found in the literature, i.e, Fodor [13], Rábai and Vad [14], Hegedus et al [15], Füle and Hernádi [16], Goda and Bánhidi [17], Bidar et al [18], Khrabry et al [19], and Fenyvesi and Horváth [20].…”

Numerical Analysis of Thermal and Aerodynamic Fields in a Channel with Cascaded Baffles

“…The influence of the buoyancy force intensity, the porous blocks shape going from the rectangular shape to the triangular shape, their height, the porous medium permeability, the Reynolds number and the thermal conductivity ratio was analyzed. Other similar works can be found in the literature, i.e, Fodor [10], Rábai and Vad [11], Hegedus et al [12], Füle and Hernádi [13], Goda and Bánhidi [14], Bidar et al [15], Khrabry et al [16], and Fenyvesi and Horváth [17]. The form geometry of the baffle is also a necessary structural parameter for the enhancement of the heat transfer phenomenon inside a channel, for example, ꞌLꞌ-shaped [18], discrete ꞌVꞌ and ꞌVꞌ-orifice [19], double ꞌVꞌ [20], diamond [21], helical [22], waisted triangular [23], and ꞌZꞌ-shaped [24].…”

Enhancement of the Hydrodynamic Characteristics in Shell-and-Tube Heat Exchangers by Using W-Baffle Vortex Generators

“…Using a numerical technique, Galushchak et al [28] simulated the thermal behavior of a tube with PHT (Punched-Helical-Tape) baffles. Other flow and heat transfer structures can be found in Ghachem et al [29], Al-Rashed et al [30,31], Ghalambaz and Zhang [32], Ghalambaz et al [33][34][35], Fodor [36], Mehryan et al [37,38], Kolsi [39], Kolsi et al [40,41] [68], and Selimefendigil [69][70][71][72].…”