Nanofluids containing multiwalled carbon nanotubes and their enhanced thermal conductivities

Multiwalled carbon nanotubes (CNTs) as produced are usually entangled and not ready to be dispersed into fluids. We treated CNTs by using a concentrated nitric acid to disentangle CNT aggregates for producing CNT nanofluids. Oxygen-containing functional groups have been introduced on the CNT surfaces and more hydrophilic surfaces have been formed during this treatment, which enabled to make stable and homogeneous CNT nanofluids. Treated CNTs were successfully dispersed into polar liquids like distilled water, ethylene glycol without the need of surfactant and into nonpolar fluid like decene with oleylamine as surfactant. We measured the thermal conductivities of these nanotube suspensions using a transient hot wire apparatus. Nanotube suspensions, containing a small amount of CNTs, have substantially higher thermal conductivities than the base fluids, with the enhancement increasing with the volume fraction of CNTs. For the suspensions with the same loading, the enhanced thermal conductivity ratios are re...

[1]  Q. Xue.  Model for effective thermal conductivity of nanofluids , 2003 .

[2]  Fei Ai,et al.  Dependence of the thermal conductivity of nanoparticle-fluid mixture on the base fluid , 2002 .

[3]  P. Ajayan,et al.  Nanotubes in a flash--ignition and reconstruction. , 2002, Science.

[4]  Huaqing Xie,et al.  Thermal conductivity enhancement of suspensions containing nanosized alumina particles , 2002 .

[5]  Hongwei Xie,et al.  Thermal Conductivity of Suspensions Containing Nanosized SiC Particles , 2002 .

[6]  S. Phillpot,et al.  Mechanisms of heat flow in suspensions of nano-sized particles (nanofluids) , 2002 .

[7]  E. Grulke,et al.  Anomalous thermal conductivity enhancement in nanotube suspensions , 2001 .

[8]  J. Shim,et al.  Effect of modification with HNO3 and NaOH on metal adsorption by pitch-based activated carbon fibers , 2001 .

[9]  S. Sinnott,et al.  Carbon Nanotubes: Synthesis, Properties, and Applications , 2001 .

[10]  P. McEuen,et al.  Thermal transport measurements of individual multiwalled nanotubes. , 2001, Physical review letters.

[11]  William W. Yu,et al.  ANOMALOUSLY INCREASED EFFECTIVE THERMAL CONDUCTIVITIES OF ETHYLENE GLYCOL-BASED NANOFLUIDS CONTAINING COPPER NANOPARTICLES , 2001 .

[12]  T. Ohara.  MOLECULAR DYNAMICS STUDY IN MICROSCALE THERMOPHYSICAL ENGINEERING: CURRENT ACTIVITIES AND FUTURE IN JAPAN , 2000 .

[13]  T. Ohara, D. Suzuki,et al.  INTERMOLECULAR ENERGY TRANSFER AT A SOLID-LIQUID INTERFACE , 2000 .

[14]  Kwon,et al.  Unusually high thermal conductivity of carbon nanotubes , 2000, Physical review letters.

[15]  Y. Xuan,et al.  Heat transfer enhancement of nanofluids , 2000 .

[16]  Xianfan Xu,et al.  Thermal Conductivity of Nanoparticle -Fluid Mixture , 1999 .

[17]  J. Eastman,et al.  Measuring Thermal Conductivity of Fluids Containing Oxide Nanoparticles , 1999 .

[18]  Alokmay Datta,et al.  Observation of molecular layering in thin liquid films using X-Ray reflectivity , 1999 .

[19]  Milo S. P. Shaffer,et al.  Dispersion and packing of carbon nanotubes , 1998 .

[20]  A. Zettl,et al.  Thermal conductivity of single-walled carbon nanotubes , 1998 .

[21]  R. Hoch,et al.  High power electrochemical capacitors based on carbon nanotube electrodes , 1997 .

[22]  J. Eastman,et al.  Enhanced thermal conductivity through the development of nanofluids , 1996 .

[23]  Charles M. Lieber,et al.  Probing Electrical Transport in Nanomaterials: Conductivity of Individual Carbon Nanotubes , 1996, Science.

[24]  D. Ugarte,et al.  Aligned Carbon Nanotube Films: Production and Optical and Electronic Properties , 1995, Science.

[25]  P. Ajayan,et al.  Aligned Carbon Nanotube Arrays Formed by Cutting a Polymer Resin—Nanotube Composite , 1994, Science.

[26]  Kenji Takeuchi,et al.  The production and structure of pyrolytic carbon nanotubes (PCNTs) , 1993 .

[27]  P. Ajayan,et al.  Large-scale synthesis of carbon nanotubes , 1992, Nature.

[28]  S. Iijima.  Helical microtubules of graphitic carbon , 1991, Nature.

[29]  Robert H. Davis.  The effective thermal conductivity of a composite material with spherical inclusions , 1986 .

[30]  O. K. Crosser,et al.  Thermal Conductivity of Heterogeneous Two-Component Systems , 1962 .

[31]  M. Dresselhaus,et al.  Carbon nanotubes : synthesis, structure, properties, and applications , 2001 .

[32]  M. Ishigami,et al.  Chemical treatment of carbon nanotubes , 1996 .