Thermal conductivity and heat capacity of nanofluid based on water modified by hybrid material of composition detonation nanodiamonds-carbon nanotubes

Abstract

This paper is devoted to assessing the prospects of using a DND-CNT hybrid material to improve water’s thermophysical properties compared with pure DND and CNT. A hybrid powdered nanomaterial composed of detonation nanodiamonds-multi-walled carbon nanotubes was synthesized by growing multi-walled carbon nanotubes on the surface of nanodiamonds aggregates coated with catalyst using CCVD method for nanotubes growth. The mass fraction of CNTs in the hybrid material was 30%. Using 0.2 mass. % of the hybrid material, we managed to increase the thermal conductivity of water by 94% and increase the specific heat by 17% (at a temperature of 60 degrees) without changing the kinetic viscosity of water. Using initial detonation nanodiamonds or commercial single-walled nanotubes as an additive at the same concentration and temperature, the maximum increase in thermal conductivity was only 37%, and the maximum increase in specific heat was only 5%. Simultaneously, the mechanical mixture of detonation nanodiamonds and carbon nanotubes (in a 7 to 3 ratio) did not form stable water suspensions.