41 p a g e chapter 3 design methods and

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Chapter 3
DESIGN, METHODS AND IMPLEMENTATION
3.1 Design Criteria
 Performance; a furnace that achieves a maximum temperature of
12000C with
minimal heat loss and fuel/ power consumption
 Eco-Sustainability: to design a furnace that is friendly to the
ecosystem, as such
incomplete combustion would be avoided.
 Safety: the design should not pose danger to the operator or
others in the
neighbourhood.
 Maintainability: the furnace should be easy maintained, so that
preventive and
corrective maintenance be easily carried out.
 Cost: the design should not be expensive in terms of its capital and
operational cost
rather it should be cheap and affordable.
 Aesthetics: the design should be aesthetically pleasing without
unnecessarily
jeopardizing the performance/function of the furnace
 Durability: the furnace should be durable
 Power Sources: the design must be operable with two power sources,
selected for this

design is Gas and Electricity
3.2 Constraint
Material availability: the design is constrained by the unavailability of certain
most preferred
material in the local market
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Manufacturability: the design is to be fabricated locally, thus limiting
manufacturing
operations.
Budget/ Cost: the furnace is to be a low cost one and anything short of this in
unacceptable
thus placing a bar on the maximum amount to be spent on the project.
3.3 Design Calculation
3.3.1 Charge Material Consideration
Mild steel is taken as the design material in consideration. It is a ferrous
alloy, i.e. containing
0.2% to 2.1% carbon as hardening agent. It also contains Chromium,
Manganese, tungsten
and Vanadium. Other than a maximum limit of 2% carbon in the
manufacture of Carbon
steel, the proportion of Manganese (1.65%), copper (0.6%) and silicon
(0.6%) are fixed,
while proportions of cobalt, chromium, niobium, molybdenum, titanium,
nickel, tungsten,
vanadium and zirconium are not fixed. The percentage of carbon
content determines the
mildness of the steel. It is malleable. The ductility, hardness and mild
steel tensile strength
are a function of the amount of carbon and other hardening agents present.
Its average density
is 7861.093kg/m3 and a young modulus of about 210000MPa (Buzzle, 2015)
buzzle.com

3.3.2 Crucible Volume:
The crucible, a modified truncated cone was used to allow for circulation of
hot combustion
gases round it for adequate heat transfer. It has a volume 0.00675 m3
(6.75litres)
Using mass- density- volume relation,
……………………………………Equ.3.1
Thus, mass = density * volume
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Therefore has a volume is capable of containing 0.00675 m3 *
7861.093kg/m3 = 53.06 kg of
mild steel.
3.3.3 Furnace Chamber Volume/Dimension:
The furnace Chamber which doubles as the combustion chamber is
cylindrical with diameter
0.29m and height 0.33m
Radius = Diameter/ 2 = 0.29/2 = 0.145m
Volume ……………………………………Equ.3.2
Volume = ( )
m3 = 21.8litres
3.3.4 Adiabatic flame Temperature of Butane Gas: this is the maximum
temperature
attainable in a combustion process in a case of no limiting heat loss to the
surrounding. It is
dependent on state of the reactant, the degree of completion of the reaction,
and the amount
of air used in the combustion process.