No abstract available

No abstract available

[en] The hypervapotron (HV) has been demonstrated to be a superior thermal management (TM) and high heat flux removal (HHFR) technique for fusion reactor plasma-facing component applications involving a single-side absorbed heat flux (up to between 20 and 30 MW/m"2 ). However, the conjugate heat transfer HV flow channel (HVFC) performance only can be optimized completely when the related HHFR controlling parameters have been identified. In an earlier work, Part I of the present effort identified four HV controlling TM and HHFR dimensionless parameters. In the present work, four additional dimensionless primary controlling parameters and five secondary controlling parameters have been identified. The controlling parameters include effects of: (1) most geometric specifications of the array of fins; (2) variations in the HV wall thermal conductivity and heat transfer coefficient; (3) effective Biot numbers charactering two-dimensional effects which include the fin array, a typical fin, and the vertical side wall; (4) HVFC unobstructive portion flow aspect ratio, and (5) the HVFC wall aspect ratio. Future work should assess the sensitivity of these parameters. (author)

[en] The description is given of a heat exchanger between a first 'hot' fluid and a second fluid to be heated, of the type comprising at least one heat exchange wall separating the fluids and through which heat is exchanged. The characteristic of this exchanger is that the wall which includes an upper end is a cyclindrical area of which the generating lines are vertical and the straight section is composed of a regular succession of undulations alternately marking peaks of convex waves and peaks of concave waves and that the exchanger includes facilities for introducing the second fluid in the upper end near the convex wave peaks of the face of the wall turned towards the second fluid

No abstract available

No abstract available

[en] In an effort to determine the combined effects of major parameters of heat exchanger tubes on the nucleate pool boiling heat transfer in the scaled in-containment refueling water storage tank (IRWST), a total of 1,966 data for q^versus ΔT has been obtained using various combinations of tube diameters, surface roughness, and tube orientations. The experimental results show that (1) increased surface roughness enhances heat transfer for both horizontal and vertical tubes, (2) the two heat transfer mechanisms, i.e.,enhanced heat transfer for both horizontal and vertical tubes, (2) the two heat transfer mechanisms, i.e., enhanced heat transfer due to liquid agitation by bubbles generated and reduced heat transfer by the formation of large vapor slugs and bubble coalescence are different in two regions of low heat fluxes (q^≤50kW/m²) and high heat fluxes (q^>50kW/m²) depending on the orientation of tubes and the degree of surface roughness, and (3) the heat transfer rate decreases as the tube diameter is increased for both horizontal and vertical tubes, but the effect of tube diameter on the nucleate pool boiling heat transfer for vertical tubes is greater than that for horizontal tubes. Two empirical heat transfer correlations for q^, one for horizontal tubes and the other for vertical tubes, are obtained in terms of surface roughness (ε) and tube diameter (D). In addition, a simple empirical correlation for nucleate pool boiling heat transfer coefficient (h_b) is obtained as a function of heat flux (q⁾ only. 9 figs., 4 tabs., 15 refs. (Author)

[en] The plate exchanger described includes a series of individual modules joined together, communicating in pairs to delimit two flow circuits separated by two fluids mutually exchanging calories. Each module includes at least one flat frame around a central cavity, at least two apertures made in the frame respectively for the inlet and oulet of the fluids crossing the cavity and at least one opening in the frame for the fluids to pass to a neighbouring module. The frames of the modules form a stack plane upon plane and are isolated by a thin leak-tight sheet parallel to the plane of the frames and separating the fluid substances in two superimposed frames. The heat transfer between these fluids occurs through this thin sheet from one module to the next in the stack

[en] This invention refers to encased tubular exhangers and can be used in nuclear power plants employing a fluid or gases as coolant. In the proposed exchanger, the hydraulic resistance of the intake and outlet stages becomes minimal as the coolant enters and leaves the tube bundle centrally. Further, because of the reductions in the hydraulic resistance of the intake and output stages of the exchanger, a maximum uniformity in the distribution of the coolant consumption is achieved according to the cross sections of the heat exchanger tube bundle, which is not dependent on the dimensions of the heat exchanger. Additionally, the temperature range of the coolant becomes regular owing to the even distribution in the coolant consumption with the cross section of the tube bundle

[en] The invention concerns a welded heat exchanger with two or more fluids which can be used counter current. The principle of the apparatus allows the use of rolled welded concentric metal strips as well as spiral rolled metal strips. The ring sheets are kept apart either by their rigidity due to the cylindrical shape or by deformations in the sheets themselves or yet again by spacers or chequered and/or perforated sheets forming for instance corrugated spacers, the end sheet being thick enough to take the pressure strain