Turbulent acidic jets and plumes injected into an alkaline environment

Abstract

The characteristics of an acidic turbulent jet and plume injected into an alkaline environment are examined theoretically and experimentally. Fluid-flow and chemistry models are combined to understand how the concentration of acid in a parcel of fluid changes as it reacts with alkaline fluid entrained from the ambient. The resulting model is tested in an experimental study in which nitric acid jets or plumes are injected into a large tank containing a variety of alkaline substances. A video camera records a pH-sensitive dye in the jet or plume, which changes colour with variations in the pH. The results were time averaged and processed to measure distance from the source to the point of neutralization. The agreement between predictions and observations of neutralization distances is good, confirming that the model captures the salient physics of the problem. Using empirically determined titration curves, a combined fluid flow and chemistry model is applied to discuss the environmental implications of a warm acidic turbulent plume injected into an alkaline river or sea.

Turbulent thermals with chemical reaction

“…The thermal only turned completely yellow when all of its volume had mixed and reacted. In turbulent plumes with instantaneous chemical reaction (Ülpre, Eames & Greig 2013), the presence of reacted and unreacted parcels within the plume has also been observed in the laboratory but was not commented upon by the authors. The unmixed blue parcels of the thermal here, where reaction is yet to occur, appear distributed throughout the whole thermal and strongly affect chemical conversion.…”

Numerical Simulation and Validation in Scrubber Wash Water Discharge from Ships

“…Theoretical and numerical analysis was conducted to comply with the regulation on the scrubber wash water discharge from ships. In the theoretical chemical models, the pH was calculated based on the initial pH and dilution ratio [9,17]. The volume fraction at 4 m from the discharge point was calculated through dispersion analysis of the turbulent jet flow.…”

“…In this study, modeling was based on the acid-weak alkali reaction reported in the works of Ülpre et al [9] and Ülpre [17]. These chemical reactions are detailed in said references.…”

“…A buffer solution is a solution that absorbs hydrogen ions even when a small amount of acid is added and thus causes almost no change in pH. The buffer capacity of seawater is mainly determined by the HCO − 3 and CO 2− 3 ions [9,18]. The chemical equilibrium of the acid HA and the base MOH is expressed as follows:…”

“…Üplre et al [9] theoretically and experimentally investigated the discharge of acidic turbulent jets in an alkaline environment. Their chemical model matched well with their titration experiment results.…”