Research of Inorganic Heat Transfer Element Starting Proprerty
Copyright © 2013 SciRes. JPEE
As shown, when the inclination angle θ are 90˚, 45˚
and 15˚, the starting property of inorganic heat transfer
element is good. The characters: When the heating power
is Q = 500 W, during the first 10 minutes of heating, the
surface temperature of inorganic heat transfer element
rises quickly, then drops in a small range (generally 2˚C
~ 3˚C) when reaches a certain temperature (about 38˚C),
which is the inflection po int on the curve; During 10 ~ 15
minutes, the temperature raise is gentle gradually; At
about the 25th minutes, the temperature is keeping a sta-
ble value, we can believe that the inorganic heat transfer
element is started totally and in a stable working state.
3.3. Starting Property with Same Inclination
Angle and Different Heating P ower
Experiment condition: Inclination angle θ is 45˚; Inlet
temperature of cooling water T g = 15˚C; Flow quantity of
cooling water Gwater = 100 L/h; Study the star ting prop-
erty of inorganic heat transfer element when the heating
power are 250 W, 500 W and 1000 W. The results are as
shown as Figure 6.
As shown, the wall temperatures of adiabatic section
under different heating power are in a same changing
trend, and all have a temperature drop inflection point on
the curve where the temperature is about 38˚C, which is
the same as Figure 5. With higher power, the surface
temperature of adiabatic section rises faster, the curve
slope is bigger, and the inflection point temperature is
higher; Then the temperature rises slowly, and gradually
reaches a stable state; The bigger of the heating power,
the higher of the adiabatic section surface temperature
under stable state.
3.4. Starting Property of Element with Different
Temperature of Cooling Medium
Experiment condition: Same inclination angle θ = 90˚;
Same flow quantity of cooling medium G water = 150
Figure 6. Starting property with same inclination angle and
differe nt heating power .
L/h; Same heating power Q = 1000 W; Different inlet
temperature of cooling water (Tg = 20˚C, 30˚C). Study
the starting property of inorganic heat transfer element.
The results are as shown in Figure 7.
As shown, the wall temperature of adiabatic section
with different inlet te mperature of cooling med ium are in
the same changing trend, and all have a temperature drop
inflection point on the curve where the temperature is
38˚C. With higher inlet temperature of cooling medium,
the surface temperature of adiabatic section rises faster,
the curve slope is bigger, and the inflection point tem-
perature is higher. The higher of the cooling medium
inlet temperature, the faster of the element starting and
the higher of the relevant temperature under stable state.
3.5. Starting Property of Element with Different
Kinds of Cooling Medium
Experiment condition: Same inclination angle θ = 90˚;
Same heating power Q = 500 W; Same flow quantity of
cooling medium G water = 200 L/h; Same inlet tempera-
ture of cooling medium Tg = 20˚C. Study the starting
property of inorganic heat transfer element with different
kinds of cooling medium (oil and water). The results are
as shown in Figure 8.
As shown, when the oil is used as the cooling medium,
within the first 10 minutes of heating, the temperature
rises faster, and the relevant temperature u nder stable state
is higher than the temperature when the water is used.
This is because the specific heat of oil is much smaller
than water, it needs to increase more temperature than
water when transfers the same quantity of heat, so the
temperature of inner medium is much higher.
4. Conclusions
1) When the inclination angle θ is 5˚ and abo ve 5˚, the
inorganic heat transfer element can be started normally,
and reach a stable state at about the 25th minutes when
continuously hea te d.
Figure 7. Starting property with different inlet temperature
of cooling medium.