Bubble frequency and departure diameter

The bubble formed at the wall grows by vaporization until it reaches a limiting volume when it detaches itself from the wall and rises. In slow growth this limiting volume is determined by the equilibrium of buoyancy and surface forces and the adhesion conditions at the wall. The decisive differential equation for this was first solved numerically by Bashfort and Adams [4.51]. Based on their solution, Fritz [4.52] later showed that there is a greatest volume VA for a vapour bubble, that can be represented in the form 

If this is formed with the saturation values g and g of the densities, then, for example, for water at 100 °C the value h = 3.54 mm is obtained, and for the refrigerant R134a at 25 °C h = 1.18 mm. Some values for air bubbles in a liquid are presented in Table 4.1. Eq. (4.83) has been confirmed by Fritz and Ende [4.53] 

4 Convective heat and mass transfer. Flows with phase change 

Equations for the calculation of the frequency f of vapour bubbles of departure diameter dA, originally started with the assumption that fdA = const, where the constants for water and carbon tetrachloride were found to be lOOmm/s [4.60]. The constants were later expressed in terms of the physical properties of the boiling liquid, 

Under the assumption that at the moment of detachment the bubbles do 

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