Viscosity measurement dataset for a water-based drilling mud-carbon nanotube suspension at high-pressure and high-temperature.

This data article presents the measured viscosity of a carbon nanotube (CNT) suspension in water-based drilling mud, also termed as nano-muds ("Rheology of a colloidal suspension of carbon nanotube particles in a water-based drilling fluid" Anoop et al., 2019). The apparent viscosity values of the nano-mud samples are measured using a high-pressure high-temperature viscometer at different shear rates, working based on a rotor and bob technique. The pressure and temperature of the samples are independently varied during the measurements from ambient conditions to 171 MPa and 176 °C, respectively, within two experimental schedules. Viscosity measurements for varying nanoparticle concentration, shear rate, pressure, and temperature are reported here for different CNT concentrations.

nPIV velocity measurement of nanofluids in the near-wall region of a microchannel.

Colloidal suspensions of nano-sized particles in a base fluid, nanofluids, have recently gained popularity as cooling fluids mainly due to their enhanced heat transfer capabilities. However, there is controversy in the literature on the reported properties of nanofluids and their applicability, especially since there is no fundamental understanding that explains these enhancements. A better understanding of these fluids and how they interact with a solid boundary may be achieved by a detailed near-wall fluid flow study at nanoscale. This work presents for the first time the near-wall velocity measurements for nanofluids using nanoparticle image velocimetry. This novel technique uses evanescent illumination in the solid-fluid interface to measure near-wall velocity field with an out-of-plane resolution on the order of O(100 nm). Nanofluids of different concentrations were prepared by dispersing silicon dioxide particles (10 to 20 nm) in water as the base fluid. Initially, viscosity measurements were conducted for the prepared nanofluids. The near-wall velocity data were then measured and compared with that of the base fluid at the same flow condition. It was observed that even though nanofluid viscosity had increased with particle loading, the near-wall velocity values were similar to that of the base fluid for a given flow rate. Together, these measurements vindicate the homogenous and Newtonian characteristics of the nanofluids in the near-wall region. Despite the low particle concentrations investigated, the present work also discusses the complexity involved in utilizing the methodology and possible errors arising during experimentation so as to implement this measurement tool more effectively in the future.