Methods for Determining the Marangoni Numbers in Studying the Absorption in the Operation of a Heat Pump

It is analyzed whether or not experimental data on the surface tension of an aqueous lithium bromide solution with or without surfactants can be used to study the heat and mass transfer in the operation of the absorber of a heat pump. Examples of the erroneous determination of the Marangoni numbers under these conditions are given. A method for calculating the interfacial tension gradients and the Marangoni numbers is proposed. It is argued that it is necessary to perform additional experimental investigations for determining the interfacial tension under the conditions of equilibrium in the surfactant-containing aqueous lithium bromide solution-water vapor system at constant water vapor pressure.