Natural convection effects in electrochemical systems

Natural (free) convection influences electrochemical processes that occur in areas as disparate as electroanalytical sensing and copper electrorefining. The modeling of natural convection requires solving a set of coupled partial differential equations reflecting the interplay between the transport of mass, heat and momentum that lies at the core of this phenomenon. This article reviews recent developments in the study of the subject, and covers various cases, e.g. free convection driven by concentration and/or temperature gradients, bubble-induced convection, and natural convection coupled with an external force. Literature on free convective flows in practical contexts such as fuel and thermogalvanic cells and electrochemical sensors is also discussed. Recent articles that describe experimental approaches for minimizing the effect of natural convection are covered. Studies which take advantage of the analogy between mass and heat transfer in order to probe the latter are discussed in brief. Particular attention is devoted to a critical assessment of the concept of ‘spontaneous convection’, which has been invoked in a number of recent papers