METHOD FOR MEASURING LIQUID FLOW VELOCITY Russian patent published in 2005 - IPC

FIELD: measurement technology; measuring velocity of single-phase laminar and turbulent flow of liquid.

SUBSTANCE: proposed method includes pulsed power delivery from ac power supply to metering thermocouple junction; heating of metering thermocouple junction; measurement of power N and pulse time τ; measurement of junction temperature on descending section of T_j = f(τ) curve; evaluation of junction cooling rate on descending branch of T_j = f(τ), m = -(dT_j/dτ)/(T_j - T_l) curve, where T_j and T_l are junction and liquid temperatures, respectively; calculation of heat-transfer coefficients α_as and α_des from dependencies α_des = mcρV/F and α_as = N/F(T_j - T_l), where F is junction surface; V is junction volume; c and ρ are thermal capacity and density of junction material, respectively; calculation of mean value of heat-transfer coefficient α_m = (α_as + α_des)/2; calculation of liquid flow velocity W from W = f(α_m ) dependence; pulse time τ_m is chosen from condition of regular junction heating time τ_r, τ_m ≥ τ_r found from condition that m_as = -(dT_j/dτ)/(T_j - T_l) = idem with time.

EFFECT: enhanced flow velocity measurement accuracy.

1 cl, 3 dwg