Investigation into Taylor-Couette-Poiseuille flow heat transfer for supercritical carbon dioxide turbomachinery

Abstract

In recent years there has been significant research in the area of supercritical carbon dioxide (sCO 2 ) closed-loop Brayton cycles as a possible alternative to conventional steam Rankine cycles due to their many advantages. These advantages include, a simpler cycle configuration, higher thermal efficiency, smaller component size and strong compatibility with renewable heat sources such as concentrated solar thermal. In order to make sCO 2 power cycles commercially available, a number of design challenges remain which must be addressed.Several design challenges arise in the sCO 2 turbine component due to its reduction in relative size.This decreases the relative distance between the rotor and temperature sensitive components, such as seals and bearings. An effective thermal management zone between the rotor and these components is required to appropriately manage the temperature of the shaft. This has been done in the past by removing heat over a long shaft, managing the temperature and mitigating thermal stresses. However, as the turbine reduces in size, the shaft speed must increase in order to maintain turbine efficiency.

Taylor-Couette-Poiseuille flow heat transfer in a high Taylor number test rig

“…Then, select the longest period over which to average to give the most accurate measurement. The time period selection process is described in significantly more detail in Chapter 5 of Swann (2020). The mean HTC value for the test displayed in Figure 9, produced in this way, is 1:67 + 0:9 Â 10 2 W/m 2 K.…”

“…The final HTC value is then evaluated by averaging the raw HTC values over the chosen time interval. Further description of this process is provided in previous publications (Swann, 2020).…”