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Technical Paper

The Current Development of Nanofluid Research

2005-04-11
2005-01-1929
It has been shown that the addition of a small amount of nanoparticles into a fluid results in anomalous increase in the thermal conductivity of the mixture, and the resulting nanofluid may provide better overall thermal management and better lubrication in many applications, such as heat transfer fluids, engine oils, transmission fluids, gear oils, coolants and other similar fluids and lubricants. The potential benefits of this technology to the automotive and related industries would be more efficient engines, reduced size and weight of the cooling and propulsion systems, lowered operating temperature of the mechanical systems, and increased life of the engine and other mechanical systems. The new mechanisms for this phenomenon of anomalous thermal conductivity increase have been proposed. The heat transfer properties of a series of graphite nanofluids were presented, and the experimental results were compared with the conventional heat transfer theory for pure liquids.
Technical Paper

Automatic Freeze Point Determination in Ethylene Glycol Based Engine Coolants

2000-06-19
2000-01-1981
Automatic equipment based on optical detection has been used for petroleum products successfully. Examples include ASTM D5773 Standard Test Method for Cloud Point Determination of Petroleum Products and ASTM D5972 Standard Test Method for the Freezing Point of Aviation Fuels. Recently it has been shown that the technology can be extended to engine coolants1. The determination of freezing point in aqueous ethylene glycol based systems is imperfectly understood and complicated by non-equilibrium solidification. The current ASTM D 1177-94 method includes manual seeding to overcome this but requires a cryogenic bath, time and considerable operator skill. Experimentally determined aqueous ethylene glycol freezing points show good agreement between laboratories only to approximately 60 wt %. In the 58 wt % to 80 wt % region, one, two and even three eutectics have been reported at varying temperatures.
Technical Paper

Standard Test Method for Cavitation and Erosion-Corrosion Characteristics of Aluminum Pumps with Engine Coolants

2001-03-05
2001-01-1181
The ASTM D 2809 test method, “Standard Test Method For Cavitation Corrosion and Erosion-Corrosion Characteristics of Aluminum Pumps With Engine Coolants” was first published in 19691. The method involves a copper-pipe circuit through which coolant solution, heated to 113°C, is pumped at 103 kPa for 100 hours. The method was modified to change the pump used in the test in 1989. It was updated in 1994 to accommodate a change in the cleaning procedure and was subsequently reapproved by the ASTM D-15 Committee on Engine Coolants in 1999.2 Tests recently conducted on several modern coolants have produced “failing” results, but the coolants are performing well in the field. Further, the repeatability and reproducibility of the method have been questioned. A round-robin series of tests sponsored by the Ford Motor Company revealed significant variations and cause for concern.
Technical Paper

Effect of Soot Loading on the Thermal Characteristics of Diesel Engine Oils

2001-05-14
2001-01-1714
When compared with new oil, used diesel engine oils exhibited thermal conductivity that increases as the concentration of soot increases. The magnitude of the effect depends on the oil composition, and on the size and dispersion of the soot particles. Although soot in engine oil is generally deleterious to engine performance from the standpoint of wear and deposits, no negative effects were observed on the thermal performance of the oil itself; indeed, even slight positive effects are expected for oils that maintain soot in stable dispersion. Therefore, the thermal challenge for engine oils in diesel engines that use exhaust gas recirculation will be to prevent soot deposition on engine surfaces.
Technical Paper

Nanofluids for Vehicle Thermal Management

2001-05-14
2001-01-1706
Applying nanotechnology to thermal engineering, ANL has addressed the interesting and timely topic of nanofluids. We have developed methods for producing both oxide and metal nanofluids, studied their thermal conductivity, and obtained promising results: (1) Stable suspensions of nanoparticles can be achieved. (2) Nanofluids have significantly higher thermal conductivities than their base liquids. (3) Measured thermal conductivities of nanofluids are much greater than predicted. For these reasons, nanofluids show promise for improving the design and performance of vehicle thermal management systems. However, critical barriers to further development and application of nanofluid technology are agglomeration of nanoparticles and oxidation of metallic nanoparticles. Therefore, methods to prevent particle agglomeration and degradation are required.
Technical Paper

Cavitation Erosion-Corrosion Testing in Aluminum Pumps with Engine Coolants

1999-03-01
1999-01-0136
The development of a laboratory test for cavitation erosion corrosion of aluminum pumps with engine coolants is described. It is based on the standard ASTM D2809 test stand but incorporates the pump and cover from a Chrysler 5.9l (360 cu. in.) engine. Operating conditions are varied to simulate components taken from vehicle service. Light duty vehicle service results, obtained in the Colorado Rocky Mountains, for three types of coolant technology with the test pump are presented. Field results include large variations in cavitation protection. Included were two organic acid (OA) coolants, a traditional North American silicate and a European OA silicate hybrid. Comparisons are drawn with the standard ASTM D2809 test, additional components are presented and corrosion morphology discussed.
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