Dynamic Viscosity Of Aqueous Solutions Research Articles

Вплив поверхнево-активних речовин на поверхневий критерій в ламінарному приграничному шарі

Показано, що на межі потік теплоносія − стінка трубопроводу, тобто в межах ламінарного приграничного шару (ЛПШ), виникає потужне поле сил поверхневого натягу. Інтенсивність поверхневих сил характеризується поверхневим критерієм. Експериментально знайдено значення коефіцієнта поверхневого натягу , косинуса кута змочування та динамічного коефіцієнта в’язкості водних розчинів під впливом поверхнево-активних речовин (ПАР). До водних розчинів додавались найбільш поширені аніонна, неіонна та катіонна ПАР. Визначені оптимальні концентрації цих ПАР до «льодяної» води. Встановлено, що за оптимальних концентрацій ПАР значення поверхневого натягу є мінімальним. Обчислено середню товщину ламінарного приграничного шару за додавання до води оптимальних концентрацій досліджуваних ПАР. Встановлено, що зменшення коефіцієнта поверхневого натягу мінімізує товщини ЛПШ у системі стінка трубопроводу-вода. Показано, що середня швидкість в пристінних шарах за додавання оптимальних концентрацій досліджуваних ПАР зростає, і як наслідок така система здатна ефективніше передавати кількість тепла. Визначено числові діапазони поверхневого критерію для «льодяної» води за додавання різного виду ПАР.

Viscosity of aqueous solutions of sodium chloride

An equation for describing the dynamic viscosity of aqueous solutions of sodium chloride in the concentration range of 0 to 6m at temperatures from 0 to 325°C and pressures up to 40 MPa is presented.

Dynamic viscosity of aqueous solutions of salts at high temperatures, pressures, and concentrations

A generalized formula for obtaining calculated values of the dynamic viscosity of aqueous solutions of salts is presented. With the use of this formula new values of the dynamic viscosity of aqueous solutions of salts BaCl2, KCl, KNO3, K2CO3, LiNO3, Li2SO4, MgCl2, and NaCl at high state parameters have been obtained.

Thermal Conductivity and Viscosity of Aqueous of Mg(NO3)2, Sr(NO3)2, Ca(NO3)2, and Ba(NO3)2 Solutions

The experimental data of thermal conductivity and dynamic viscosity of aqueous solutions of the alkaline earth metals' nitrates in temperature range (298.15 to 598.15) K, pressure (0.1 to 40) MPa, and molality for H2O + Mg(NO3)2 (0.7507, 1.689, 2.8950, and 4.5040) mol·kg-1, for H2O + Sr(NO3)2 (0.525, 1.181, 2.025, and 3.150) mol·kg-1, for H2O + Ca(NO3)2 (0.6771, 1.5235, 2.598, and 4.063) mol·kg-1, and for H2O + Ba(NO3)2 (0.0781, 0.1594, 0.2442, and 0.3327) mol·kg-1 have been summarized. The measured values of thermal conductivity and viscosity were compared with data and correlations reported in the literature. A relationship between relative dynamic viscosity and relative thermal conductivity is established. A correlation equation relating relative dynamic viscosity and thermal conductivity of aqueous solutions was obtained as a function of temperature and composition. The equation describes values of viscosity within ± 2.2 %.

Thermodynamic Characteristics of a Viscous Flow in Aqueous Solutions of Barium Nitrate

An experimental investigation of the dynamic viscosity of aqueous solutions of Ba(NO3)2 at temperatures of 298–598 K and pressures of 5–40 MPa is carried out on a setup based on the extension-capillary method. The uncertainty of the data does not exceed 1.5%. An equation that describes the experimental data is constructed. The free energy and enthalpy of viscous flow activation have been calculated.

Viscosity of aqueous solutions of some alkali cyclohexylsulfamates at 25.0 °C

The dynamic viscosity of aqueous solutions of cyclohexylsulfamic acid and of its lithium, sodium and potassium salts was measured in the concentration range from 0.02 to 0.70 mol dm −3 (the potasssium salt only up to 0.20 mol dm −3 because of its poor solubility) at a temperature of 25.0 °C. The data for relative viscosity, which were calculated from the dynamic viscosity, were analysed with the help of the extended Jones–Dole equation and the viscosity coefficients A η , B η and D η were evaluated. The B η coefficients of the salts were divided into their ionic contributions and the ionic B η value for the cyclohexylsulphamic ion was determined. From the viscosity coefficient B η the partial molar Gibbs energy of activation for viscous flow at infinite dilution was calculated for the investigated solutes and interpreted in terms of relative solute effects on the solvent in the ground and in the transition states. Additionally, the hydration number of the solute was determined and some correlation between the transport properties of solutions of cyclohexylsulphamates and their relative sweetness was found.

Densities and Viscosities of Ternary Systems of Water + Glucose + Sodium Chloride at Several Temperatures

The density and dynamic viscosity of aqueous solutions of sodium chloride, glucose, and glucose + sodium chloride were measured at temperatures from (20 to 40) °C. The concentration range studied for both sodium chloride and glucose was (0 to 4) mol·kg-1. The experimental values of the ternary system were correlated as a function of the salt concentration. In addition, neural networks were used to simulate changes in density and viscosity of the systems studied with temperature and concentration in the ranges mentioned.

Dynamic viscosity of aqueous solutions of hydrazine with high state parameters

We report the results of measurements of the dynamic viscosity of aqueous solutions of hydrazine with a molar concentration of water ranging from 10 to 90%, in the temperature interval 293–558.4 K and the pressure interval 0.101–58.86 MPa.

Dynamic viscosity of dilute aqueous solutions of poly(acrylic acid) at frequencies of 2–500 kHz

AbstractThe dynamic viscosity of aqueous solutions of poly(acrylic acid) at a polymer concentration of ca. 0.15 g/100 ml has been measured at frequencies from 2 to 500 kHz as a function of degree of polymerization P, degree of neutralization α, and salt (NaCl) concentration Cs. Relaxation spectra have been obtained from the dynamic viscosity. The spectra in the short relaxation time region can be approximated by the Zimm theory for the conformational relaxation of nonionic polymers. The maximum relaxation time τ1 of the Zimm spectra is proportional to P2 and depends rather moderately on α and Cs. Increased deviation is found, however, in the long relaxation time region, in particular for high values of P and α and low values of Cs. The major part of the deviation is interpreted in terms of rotational relaxation of a molecule as a whole. The rotational relaxation time τR is proportional to P3 and increases with increasing α and decreasing Cs. The remaining part of the excess spectra located between τ1 and τR is ascribed to the deviation of the conformational relaxation from the Zimm theory arising from ionization of the polymer.

Use of molecular characteristics to calculate viscosity of mineral solutions

The possibility of using molecular characteristics in the determination of the thermophysical parameters of fluids is shown. Approximate equations for the calculation of the dynamic viscosity of aqueous solutions of mineral salts are obtained through the use of similarity theory and molecular data.