Numerical study on suppressing heat transfer deterioration of supercritical CO2 in tube with wire-mesh inserts

A periodic wire-mesh inserted tube is proposed to mitigate heat transfer deterioration (HTD) of supercritical carbon dioxide in upward flow through a vertical tube. Its thermohydraulic performance is numerically investigated at p = 8 MPa, with mass flux G ranging from 400 to 3000 kg/m2 s and heat flux q ranging from 100 to 490 kW/m2. The results show that effective HTD suppression is achieved only when the wire-mesh insert is arranged upstream of the deterioration region, and increasing the number of inserts enlarges the suppression region where the wall temperature is reduced. For the periodic configuration, the peak wall temperature is reduced by 91 K, maximally. It owes to enhanced near-wall fluid renewal and radial mixing, which thin the near-wall vapor-like layer and suppress thermal-boundary-layer development. Moreover, the thermohydraulic analysis indicates that the heat-transfer enhancement factor and performance evaluation criterion generally increase first and then decrease with increasing mass flux and heat flux, accompanied by local fluctuations, reaching maximum values of 1.92 and 1.42, respectively. A mass flux–heat flux diagram is further constructed to distinguish the effective HTD suppression region from the weak HTD suppression region. The present study provides physical insights and design guidance for the HTD mitigation of supercritical carbon dioxide in channels.