الفهرس 
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Abstract
Nanofluid is an advanced kind of fluid, which contain nanometer sized (10-9 m) solid particles that are known as nanoparticles. Nanoparticles enhance the property of
Normal fluid . In past five years, nano refrigerant has become the input for large
number of experimental vapor compression systems because of shortage of energy
and environmental considerations.
This present study aims to investigate experimentally the effect of using different concentrations of the nanoparticles of CuO-R134a on the evaporating heat transfer coefficient for R-134a in vapor compression systems.
An experimental test rig is designed and constructed here for this Purpose, the test
section is a horizontal tube in tube heat exchanger made from copper.
The refrigerant is evaporating inside an inner copper tube and the heating load is provided from the hot water that passing in the annular space surrounding the inner tube.
Measurements were performed for heat flux ranged from 40 to 70 kW/m2, mass flux ranged from 120 to 220 kg/m2s using nano CuO concentrations ranged from 0.25 to 1.2% by weight. The measurements indicated that for any nano particles concentration as heat flux or mass flux increases the evaporating heat transfer coefficient increases.
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Also, the measurements indicated also that the evaporating heat transfer coefficient increases with increasing nano CuO concentrations up to 0.5% then it decreases, from the experimental measurement obtained here the following equation is drawn.
havg=A(G)+B(G)(Z)2+C(G)(q)+D(G)(Z)2+E(G)(q)2+F(G)(Z)(q)+g(G)(Z)3
+h(G)(q)3+I(G)(Z)(q)2+J(G)(q)(Z)2
This equation is valid in work conditions heat flux ranged from 40 to 70 kW/m2, mass flux ranged from 120 to 220 kg/m2s using nano CuO concentrations ranged from 0.25 to 1.2% by weight. The results show a good presentation for the deduced correlation equation with ± 10 %, maximum deviation.
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NOMENCLATURES
m2Nanofluid is an advanced kind of fluid, which contain nanometer sized (10-9 m) solid particles that are known as nanoparticles. Nanoparticles enhance the property of
Normal fluid . In past five years, nano refrigerant has become the input for large
number of experimental vapor compression systems because of shortage of energy
and environmental considerations.
This present study aims to investigate experimentally the effect of using different concentrations of the nanoparticles of CuO-R134a on the evaporating heat transfer coefficient for R-134a in vapor compression systems.
An experimental test rig is designed and constructed here for this Purpose, the test
section is a horizontal tube in tube heat exchanger made from copper.
The refrigerant is evaporating inside an inner copper tube and the heating load is provided from the hot water that passing in the annular space surrounding the inner tube.
Measurements were performed for heat flux ranged from 40 to 70 kW/m2, mass flux ranged from 120 to 220 kg/m2s using nano CuO concentrations ranged from 0.25 to 1.2% by weight. The measurements indicated that for any nano particles concentration as heat flux or mass flux increases the evaporating heat transfer coefficient increases.
iii
Also, the measurements indicated also that the evaporating heat transfer coefficient increases with increasing nano CuO concentrations up to 0.5% then it decreases, from the experimental measurement obtained here the following equation is drawn.
havg=A(G)+B(G)(Z)2+C(G)(q)+D(G)(Z)2+E(G)(q)2+F(G)(Z)(q)+g(G)(Z)3
+h(G)(q)3+I(G)(Z)(q)2+J(G)(q)(Z)2
This equation is valid in work conditions heat flux ranged from 40 to 70 kW/m2, mass flux ranged from 120 to 220 kg/m2s using nano CuO concentrations ranged from 0.25 to 1.2% by weight. The results show a good presentation for the deduced correlation equation with ± 10 %, maximum deviation.