A heat transfer dataset for supercritical carbon dioxide flowing in three directly heated tubes with internal diameters equal to 4.6, 8.0 and 22.0 mm under closely incremented and widely ranging operating conditions
Description
All experimental results were collected in the multi-fluid Supercritical University of Ottawa Loop (SCUOL). This facility was designed to operate at a maximum pressure of 10 MPa and contained carbon dioxide as the working fluid. Measurements were collected in three electrically heated circular tubes with inner diameters D = 4.6, 8.0 and 22.0 mm, wall thicknesses 0.89, 1.00, and 1.50 mm and heated lengths of 1200, 1940 and 2000 mm, respectively; each heated test section was preceded by an unheated section of the same tube. Wall temperature was measured by closely spaced, surface mounted, T-type thermocouples. The bulk fluid specific enthalpy along the heated test section was calculated using the energy equation. Local values of the carbon dioxide thermophysical properties were computed from specified values of pressure and temperature using the NIST software. The three datasets, one for each test section, include wall temperature, bulk temperature, and heat transfer coefficient profiles for each condition measured. The conditions include a reduced pressure that was 1.13 times the pressure of supercritical carbon dioxide. The mass flux (G) was incremented by increments of 100 kg/m^2s up to G = 700 kg/m^2s, with measurements also taken at G = 1000 and 1500 kg/m^2s for the 4.6 and 8 mm test sections. For each G, measurements were taken for three or four different wall heat fluxes (q) at levels slightly below and above the corresponding value at heat transfer deterioration onset. For each of the mass flux and heat flux combinations, tests were performed for inlet temperatures in the range 0 ◦C <Tin<36 ◦C, with increments of approximately 3 ◦C.