University:
North Idaho College
Course:
PHYS-211 | Engineering Physics I
Academic year:

2023
Views:

405

Pages:

3
Author:

Hani T.

Effect of Temperature on Viscosity. The effect of increasing Temperature Causes a decrease in Viscosity η, as the Intermolecular forces are weakened, Arhenius and Guzman Showed that: η = Ae^(-En/RT) Where A is a constant, En is the activation energy for viscous flow and T is the Temperature in the absolute Scale ln η = ln A + En/RT Effect of Temperature on Viscosity. The effect of increasing Temperature Causes a decrease in Viscosity η, as the Intermolecular forces are weakened, Arhenius and Guzman Showed that: η = Ae^(-En/RT) Where A is a constant, En is the activation energy for viscous flow and T is the Temperature in the absolute Scale ln η = ln A + En/RT log₁₀ η = En / (2.303RT) + Constant Plots of log₁₀ η versus 1/T allow an estimate of En for the fluid. Some Data on η at various Temperatures is Below Viscosities (centipoise) T(K°) Liquid 273 293 313 333 353 Water 1.792 1.005 0.656 0.469 0.356 Ethanol 1.773 1.200 0.834 0.592 Benzene 0.912 0.652 0.503 0.392 0.329 Carbon Tetrachloride 1.329 0.969 0.739 0.585 0.468 Mercury 1.685 1.554 1.450 1.367 1.240 The viscosities of most liquids thus decrease with increasing Temperature According to the Theory of liquids there are Vacancies in a Liquid and Molecules are Continually moving into these vacancies, and the vacancies also move. This process permits flow, However, Movement into vacancies needs an activation energy.