Hydraulic resistance of fluids flowing in channels at supercritical pressures (survey)

This literature survey is devoted to hydraulic resistance of water and carbon dioxide flows at supercritical pressures. The objectives are to assess previous studies that were done in the area of hydraulic resistance of fluids at supercritical pressures flowing in channels of various geometries and to understand the specifics of pressure drop at these conditions. The literature search showed that the majority of experimental data were obtained in vertical tubes, some data were obtained in horizontal tubes and just a few of them in other flow geometries including bundles. In general, hydraulic resistance data are limited compared to the heat transfer data at supercritical pressures. Differences in pressure drop between supercritical and subcritical forced convection seem to be related to significant variations in thermophysical properties near the critical and pseudocritical points. Due to these variations, satisfactory analytical and numerical methods have not yet been developed especially in turbulent flows and at high heat fluxes. In general, the pressure drop in supercritical fluid flow consists of four components: pressure drop due to frictional resistance, due to local flow obstruction, due to acceleration of flow and due to gravity. The total pressure drop at supercritical pressures can be estimated using general correlations for pressure drop at subcritical pressures with correction factors for the effect of significant thermophysical properties variations and high heat fluxes. Only one paper was devoted to pressure drop in tight short bundles cooled with water at supercritical pressures. Therefore, more experimental work is needed to estimate the total pressure drop in various bundle designs with the objective of providing reliable information for designing supercritical water nuclear reactors.