Analysis of Thermal Performance of a Car Radiator Employing Nanofluid
Ghanbarali Sheikhzadeh,
Mohammadhadi Hajilou,
Hamed Jafarian
Issue:
Volume 2, Issue 4, August 2014
Pages:
47-51
Received:
10 August 2014
Accepted:
29 August 2014
Published:
20 September 2014
Abstract: In this study, thermal performance of a car radiator with employment of Ethylene Glycol/copper nanofluid in disparate environmental conditions has been investigated. The governing equations for heat transfer in the car radiator have been written and solved by using a generated computer code in different environmental states and the changes in the output nanofluid temperature have been studied. It has been shown that by increasing the values of volume fraction of nano-particles and also, Reynolds number of inlet air, one can observe a raise in the values of overall heat transfer coefficient of the air side and the rate of heat transfer. Furthermore, it is observed that by adding nano-sized particles to the coolant fluid in radiator, one can significantly reduce its output temperature. In addition, it has been demonstrated that by adding 5% of nano-particles to the coolant fluid, thermal performance of the radiator in a hot weather of 50˚ C can be better than its performance in the weather of 20˚C.
Abstract: In this study, thermal performance of a car radiator with employment of Ethylene Glycol/copper nanofluid in disparate environmental conditions has been investigated. The governing equations for heat transfer in the car radiator have been written and solved by using a generated computer code in different environmental states and the changes in the o...
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Numerical Analysis of Hydroinertia Gas Bearings with Inclined Supply Holes for High-Speed Rotary Machines
Tomohiko Ise,
Sayuri Nakano,
Toshihiko Asami,
Yuki Endo,
Itsuro Honda
Issue:
Volume 2, Issue 4, August 2014
Pages:
52-57
Received:
22 August 2014
Accepted:
9 September 2014
Published:
20 September 2014
Abstract: Hydroinertia gas journal bearings have been applied to solid-state nuclear magnetic resonance (NMR) as an example. This type of bearing can realize a stable operation for the ultra-high-speed rotation of an NMR sample tube as high as several million rpm, because these bearings utilize a large radial clearance compared with conventional externally pressurized bearings. To obtain even higher rotational speeds, inclined supply holes in the direction of shaft rotation have been proposed. The characteristics of these proposed bearings are examined in this study by numerical analysis because the actual NMR sample rotor is thin and long (with a diameter of 1 mm to 4 mm). The numerical analysis results of the hydroinertia journal bearings are reported in this study. Variation of the pressure distribution and the load capacity with respect to the effect of the radial clearance and the angle of the supply holes are described. The results show that a negative pressure is generated at large radial clearance, and the load capacity does not affect the angle. The pressure distribution was experimentally verified using a test rig, which has 10 mm diameter rotor.
Abstract: Hydroinertia gas journal bearings have been applied to solid-state nuclear magnetic resonance (NMR) as an example. This type of bearing can realize a stable operation for the ultra-high-speed rotation of an NMR sample tube as high as several million rpm, because these bearings utilize a large radial clearance compared with conventional externally p...
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