A numerical-experimental analysis of qualification assessment for mono-block plasma-facing component with flat heat sink

The heat removal capacity of a flat heat sink was studied using subcooled flow boiling experiments, to address the thermal peaking problem. Based on the Bowring criteria, the boiling curve is divided into a partially developed nucleate boiling regime (PDB) and fully developed nucleate boiling regime (FDB), and the existing heat transfer correlations for each flow regime are evaluated. In the PDB regime, the Baburajan correlation exhibited the highest prediction rate with an average error rate of 10.92%; however, the FDB regime heat transfer correlations exhibited high error rates at very high heat flux conditions. Therefore, the authors developed a new FDB correlation using the artificial intelligence technique by correlating the bubble agitation effect, which is a mechanism of the FDB regime, and then, evaluated the qualification assessment on this basis. The mono-block plasma-facing component with a flat heat sink was found to meet all criteria (except #1.2, shutdown plasma ratcheting), and to succeed in the actual fabrication.

Features of cooling bodies with a high coefficient of thermal effusivity in subcooled mixtures

The paper focuses on the study a special type of boiling, "microbubble boiling". Experiments are carried out on water-ethanol mixtures of different concentrations. The pressure varies from 0.1 to 0.3 MPa; and copper and stainless-steel samples are used as working samples. The purpose of the experiments is to investigate the effect of such parameters as solid and liquid properties and subcooling on the transition temperature from the stable film boiling to “microbubble” boiling regime. In the course of direct comparison of the results obtained by cooling the samples with different thermal effusivity under the same conditions, a strong influence of the properties of the cooled body on the quenching process has been revealed.

Investigating the effect of submerged impingement jet on heat transfer in water-alcohol mixtures

This paper presents new results of experiments on spherical sample cooling with submerged impingement jet in subcooled water-alcohol mixtures. The influence of the ethanol concentration on the occurrence of intensive boiling regime is detected. Experiments are carried out on a stainless-steel sample in a water-ethanol mixture, in a wide range of concentrations and temperatures. The result includes an increase of the heat transfer intensity at exposure of the submerged impingement jet. The intensive boiling regime is detected with a higher ethanol content compared to experiments in a calm liquid.