scholarly journals Numerical analysis of the thermal profile inside the wall of a rotary cement kiln

Cerâmica ◽  
2020 ◽  
Vol 66 (380) ◽  
pp. 496-506
Author(s):  
P. H. G. da Silva ◽  
J. Moreira ◽  
A. O. S. Costa ◽  
E. F. Costa Jr.

Abstract The present study aimed to evaluate the temperature profile along the inside of the wall of a clinker kiln from a cement industry. The problem was modeled by the equation of transient heat conduction in cylindrical coordinates, considering radial symmetry. Being the wall composed of different materials, even adopting constant physical properties, there is no analytical solution to the problem. The method of the lines was used, being the radial and axial directions discretized by finite differences and the resulting system of ordinary differential equations integrated in time until obtaining the temperature field in steady state. The obtained field was compatible with heat transfer fundamentals and presented a good fit in relation to industrial data. The main limitations of the modeling performed in this study include the fact that the gases and solids contained in the kiln have not been modeled, and the variation in thicknesses of the layers of the kiln wall has not been considered. The program developed in this study can be used to evaluate the performance of different refractories or to infer the refractory wear level from experimental kiln surface temperature profiles.

2012 ◽  
Vol 134 (12) ◽  
Author(s):  
Rajai S. Alassar

The transient heat conduction from two parallel isothermal cylinders is studied using the naturally fit bipolar cylindrical coordinates system. The energy equation is expanded in a Fourier series using appropriate basis functions to eliminate one of the physical coordinates. The resulting modes of the expansion are solved using a finite difference scheme. It is shown that, as is the case with a single isothermal cylinder in an infinite medium, steady states for two isothermal cylinders are not possible and heat transfer changes indefinitely with time.


1998 ◽  
Vol 26 (1) ◽  
pp. 51-62
Author(s):  
A. L. A. Costa ◽  
M. Natalini ◽  
M. F. Inglese ◽  
O. A. M. Xavier

Abstract Because the structural integrity of brake systems and tires can be related to the temperature, this work proposes a transient heat transfer finite element analysis (FEA) model to study the overheating in drum brake systems used in trucks and urban buses. To understand the mechanics of overheating, some constructive variants have been modeled regarding the assemblage: brake, rims, and tires. The model simultaneously studies the thermal energy generated by brakes and tires and how the heat is transferred and dissipated by conduction, convection, and radiation. The simulated FEA data and the experimental temperature profiles measured with thermocouples have been compared giving good correlation.


1993 ◽  
Vol 17 (2) ◽  
pp. 145-160
Author(s):  
P.H. Oosthuizen ◽  
A. Sheriff

Indirect passive solar crop dryers have the potential to considerably reduce the losses that presently occur during drying of some crops in many parts of the “developing” world. The performance so far achieved with such dryers has, however, not proved to be very satisfactory. If this performance is to be improved it is necessary to have an accurate computer model of such dryers to assist in their design. An important element is any dryer model is an accurate equation for the convective heat transfer in the collector. To assist in the development of such an equation, an experimental and numerical study of the collector heat transfer has been undertaken. In the experimental study, the collector was simulated by a 1m long by 1m wide channel with a gap of 4 cm between the upper and lower surfaces. The lower surface of the channel consisted of an aluminium plate with an electrical heating element, simulating the solar heating, bonded to its lower surface. Air was blown through this channel at a measured rate and the temperature profiles at various points along the channel were measured using a shielded thermocouple probe. Local heat transfer rates were then determined from these measured temperature profiles. In the numerical study, the parabolic forms of the governing equations were solved by a forward-marching finite difference procedure.


Author(s):  
Tunc Icoz ◽  
Qinghua Wang ◽  
Yogesh Jaluria

Natural convection has important implications in many applications like cooling of electronic equipment due to its low cost and easy maintenance. In the present study, two-dimensional natural convection heat transfer to air from multiple identical protruding heat sources, which simulate electronic components, located in a horizontal channel has been studied numerically. The fluid flow and temperature profiles, above the heating elements placed between an adiabatic lower plate and an isothermal upper plate, are obtained using numerical simulation. The effects of source temperatures, channel dimensions, openings, boundary conditions, and source locations on the heat transfer from and flow above the protruding sources are investigated. Different configurations of channel dimensions and separation distances of heat sources are considered and their effects on natural convection heat transfer characteristics are studied. The results show that the channel dimensions have a significant effect on fluid flow. However, their effects on heat transfer are found to be small. The separation distance is found to be an important parameter affecting the heat transfer rate. The numerical results of temperature profiles are compared with the experimental measurements performed using Filtered Rayleigh Scattering (FRS) technique in an earlier study, indicating good agreement. It is observed that adiabatic upper plate assumption leads to better temperature predictions than isothermal plate assumption.


2007 ◽  
Vol 62 (9) ◽  
pp. 2590-2607 ◽  
Author(s):  
Kaustubh S. Mujumdar ◽  
K.V. Ganesh ◽  
Sarita B. Kulkarni ◽  
Vivek V. Ranade

2018 ◽  
Vol 21 (4) ◽  
pp. 1104-1119 ◽  
Author(s):  
Andrew W. Wharmby

Abstract A new lumped capacitance model that employs fractional order operators is proposed for use on transient heat conduction problems. Details and implications of the fractional lumped capacitance model’s development and application are discussed. The model is shown to agree with observed heating and cooling temperature profiles of laser aiming paper being heated by a laser under various conditions.


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