Performance Analysis and Reliablity Testing of a Ceramic Bake Ware for an Electric Injera Baking Stove
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Date
2015-04
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Addis Ababa University
Abstract
In this study, the suitability and reliability of a ceramic bake ware based electric stove
(CBWBES) for injera baking application were assessed experimentally and a mathematical
model of the coupled heat and mass transfer of the baking process was developed and solved
using Finite Element (FE) method. MATLAB code was used to perform the FE analysis,
which is then used to estimate the performance of the CBWBES for different numbers of
baking cycles.
The FE model was first validated using experimental data obtained from field testing of the
performance of the CBWBES. The reliability of the CBWBES was investigated for its
thermal shock resistance by subjecting the mitad in cycles of baking, and heating and cooling
tests from (180 to 210 oC). Regarding the suitability of the new ceramic mitad While; two
injera baked at mitad top surface temperature of 210oc Shows poor product quality formation
10 injera baked at a reduced temperature of 147 to 150oc Shows its suitability for the intended
application. The CBWBES passed 12 cycles „of injera baking and 6 heating and air cooling
cycles without the occurrence of deep cracks in the body. The 10 injera produced before the
advent of the cracks was in good quality, with an excellent bottom crest formation and porous
top surface structure. The total energy intensity of the new CBWBES was calculated and
becomes 1.96 MJ/kg.; which is comparably close to the value of the conventional clay stove,
which is 1.79 MJ/kg. The higher thermal inertia of the new CBWBES yields longer heat up
times and longer times to recover the baking surface temperature once injera is baked; this
was mainly attributed to the increased thickness of the bake ware used for the present test.
The heat up time obtained experimentally closely matched with the simulation result with an
error of less than 10 %., and the simulation shows about 82 % efficiency can be realizable by
reducing the thickness to 8mm for 20 cycles of injera baking, even though the absence of
suitable production process in manufacturing the ceramic mitad affects its quality for baking
application; based on the results obtained it could be concluded that the CBWBES can be a
very good substitute for conventional clay bake wares both for energy efficiency and good
quality of product formation provided that a reduction in the heating up time is achieved in
the new ceramic bake ware.
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Thermal Engineering Stream