Measuring maximum tensile strength of liquids at low stressing rates

A technique is presented for determining the maximum tensile strength of a given fluid through the analysis of the break-up at the end of a capillary-thinning experiment. This technique allows the characterisation of the tensile strength, an important parameter for understanding cavitation, of a fluid at lower stressing rates than previous methods, such as bullet-piston apparatus. The method was validated by tests on a range of concentrations and molecular weights of polyethylene glycol, comparing the results with the values and behaviours observed from the bullet piston apparatus. Excellent agreement was observed between the two techniques, with quantitative differences corresponding to the differences in stressing rates. The results from the capillary break-up experiments were also used to investigate the effect of concentration and molecular-weight on tensile strength.