Experimental Investigation of Boiling Heat Transfer and Pressure Drop in Swirl Flow under Conditions of One-Sided Heating

The paper gives the basic results of experimental investigation of hydrodynamics and nucleate boiling heat transfer in heat-absorbing devices of the ITER thermonuclear reactor, which are subjected to one-sided heating. Experimental data are obtained on pressure drop, heat transfer and critical heat fluxes (CHF) in the following range of parameters of water flow: pressure p = 0.7–2.0 MPa, mass flux G = 340–25 000 kg/(m2s), and water temperature at the inlet Tin = 20–60 °C. The investigations were performed for flow swirled by tapes with different values of flow swirl coefficient, as well for test sections without tape. The test-sections with a cooled channel of 2.0, 4.0, and 8.0 mm inside diameter were used. One-sided heating of the test sections were provided by the scanning electron beam injected by the electron gun. More than 500 experimental points on nucleate boiling heat transfer were obtained. The predicting equation for nucleate boiling heat transfer at one-sided heating has been proposed. A simple approach was used for the calculation of CHF. The predicting equation for CHF reliably generalizes the existing experimental data.