This study examined the cooling performance of a fuel-cooled oil cooler (FCOC) under typical operating conditions. The oil cooler can fail due to the congealing of oil in the FCOC core at low-temperature conditions, which could be recovered by de-cong...
This study examined the cooling performance of a fuel-cooled oil cooler (FCOC) under typical operating conditions. The oil cooler can fail due to the congealing of oil in the FCOC core at low-temperature conditions, which could be recovered by de-congealing the oil flow. The de-congealing time can be affected by changes in oil pressure and temperature conditions, flow re-routing, and malfunctioning of the oil bypass valve (OBV). In this study, we proposed a prediction model for the transient oil de-congealing phenomenon in the FCOC. The numerical procedure was based on the one-dimensional (1D) flow and thermal network analysis and the effectiveness (ε)-NTU method. The commercial code was customized to implement the de-congealing phenomena. Pre-defined empirical correlations and property corrections aided the modeling of the detailed de-congealing process. Moreover, the 3D CFD temperature contours provided a visual insight into the internal flow inside the FCOC core during the de-congealing process. An experimental study was conducted in parallel to validate the prediction result. Both experimental and numerical methods showed a loss of cooling when the OBV fails. The oil temperature and pressure, and flow directions affect the de-congealing process. The present model proved useful for various oil cooler configurations that are difficult to investigate experimentally and could quickly provide oil de-congealing results.