Electrodeless Investigation of Conductivity of Liquid in Capillaries with due Regard for Skin Effect

Resumo

—Processes occurring in the setup for contactless measurement of conductivity of liuids have been considered. The experimental study of the relationship of the oscillating circuit Q-factor as a function of the specific resistance of liuid was performed using the electrode and electrodeless methods of measurements. Freuency relationships of additional attenuation d in the oscillating circuit caused by the presence of liuid with specific resistance ρ in inductively coupled capillary solenoid were investigated in the freuency range 2.2–8.8 MHz. It was shown that the impact of skin effect was significant for the considered values of ρ and the additional attenuation was described by formula d = −a₀(f) + a₁(f)ρ^1/2, where function a₁(f) is proportional to f^3/2, while function a₀(f) is proportional to f². Owing to different freuency dependences of functions a₁(f) and a₀(f), the frequency relationship of the relative depth of skin layer in liquid electrolyte was obtained in explicit form: h / r_cp = A(f)ρ^½af^½ρ^½, where a is the constant that does not depend on frequency and specific resistance of liquid.