Wall effects in a diamond‐anvil pressure‐cell falling‐sphere viscometer

Abstract

A geometric correction factor γ due to the close proximity of the walls and sphere in a diamond‐anvil pressure‐cell falling‐sphere viscometer is evaluated in order to determine a liquid’s viscosity μ from the measured apparent viscosity μ_A. μ=γμ_A. Approximate values of γ are presented for a finite right circular cylindrical cell in which a sphere falls along a centrally located diameter. The results are used in conjunction with measurements on a fluid of known viscosity to estimate that the accuracy obtainable in a diamond‐anvil pressure‐cell falling‐sphere viscometer is better than 30%.