CSC 201606320242 and KoudeGroep Delft / Wageningen
Flow patterns in plate heat exchangers and local momentum, heat and mass transfer phenomena
Two-phase flow in plate heat exchanger
Plate heat exchangers (PHEs) have a wide range of applications due to their superior performance in relation to favourable heat transfer coefficients (HTCs), compactness, design flexibility and thermal effectiveness. PHEs are frequently used in refrigeration and heat pump applications but are also the preferred heat exchanger type for OTEC plants. However, the two-phase behaviour inside the PHEs is yet not fully understood, resulting in over- or underestimating by several published heat transfer and pressure drop correlations, which are limited by the range of conditions they cover. Better prediction of flow patterns in plate heat exchangers will improve the calculation of heat transfer and pressure drop. Flow patterns can be determined visually in an experimental setup where the flow is observed through a transparent plate. Flow patterns are defined by the geometric configurations of vapor and liquid and are classified into four main flow patterns: bubbly, slug, churn and film flow. The sequence of occurrence is based on the increase of the vapor mass flux.
Key research challenges / Research plan:
In order to develop a further understanding of the phenomena, the following work has been undertaken:
i. Visualization experiments and determination of distribution and flow pattern map
ii. Local heat and mass transfer performance experiments
iii. Modelling and validation of combined heat and mass transfer processes in PHEs
Tao, X., Nuijten, M.P., Infante Ferreira, C. A., (2018) Two-phase vertical downward flow in plate heat exchangers: flow patterns and condensation mechanisms. International Journal of Refrigeration, Vol. 85, pp. 489-510.
Tao, X, Infante Ferreira, C.A., (2019). “Heat transfer and frictional pressure drop during condensation in plate heat exchangers: Assessment of correlations and a new method”. International Journal of Heat and Mass Transfer, Vol. 135, pp. 996-1012.
Tao, X, Dahlgren, E., Leichsenring, M., Infante Ferreira, C.A. (2020) “NH3 condensation in a plate heat exchanger: Experimental investigation on flow patterns, heat transfer and frictional pressure drop.” International Journal of Heat and Mass Transfer, Vol. 151, 119374.
Tao, X, Infante Ferreira, C.A. (2020) “NH3 condensation in a plate heat exchanger: Flow pattern based models of heat transfer and frictional pressure drop.” International Journal of Heat and Mass Transfer, Vol. 154, 119774.