CFD Modeling of Mixing Process in Pump for Two Liquids With Different Temperatures Available to Purchase

The mixing of two or more liquids is very common in many industrial applications. In some cases the liquids are set on the pump inlet. The mixing process of two non-isothermal fluids in a pump is investigated in the presented work. Different pump geometries have been studied with comparison steady state and averaged transient results. Presented work considers the influence of the difference in temperatures of two mixing liquids on the mixing process. The pump model consists of suction, impeller and discharge parts which were meshed and calculated together. This, for instance, naturally permits the effects of non-uniformity of velocity and liquids concentrations distribution on the impeller eye and on the inlet of the discharge segment to be taken into account. Dependence of the density of liquids on the temperature is taken into account. Results of previous work with isothermal liquids demonstrated significant change in the mixing uniformity coefficient γ depending on where on the inlet the injected fluid is located and effect of very fast fading oscillations of concentration with blade passing frequency. For injection with angular symmetry on the pump inlet, γ is close to 1 (ideal mixture) on the outlet compared with γ less than 0.9 for strong angular asymmetry injection on the pump inlet, which is not sufficient for some applications. Results of presented work show the small, but visible, difference in the mixing uniformity coefficient for isothermal and non-isothermal liquids with the same flow rates on the inlet. Temperature uniformity coefficient is very close to the mixing uniformity coefficient, which is obvious, because of closeness of turbulent diffusivity and thermal conductivity coefficients.