Thermodynamic analysis of lead–bismuth eutectic turbulent flow in a straight tube

• Classical turbulence model can well describe heat transfer and flow of LBE.
• Heat transfer entropy generation predominates in the total entropy generation.
• Increasing cooling heat flux in axial direction is better than decreasing one.

The entropy generation in Lead–Bismuth Eutectic (LBE) turbulent flow in a cooled straight tube with a diameter of 10 mm and a length of 1 m is numerically investigated taking into account the temperature-dependent of LBE properties. The standard k-epsilon turbulence model combined with appropriate turbulence Prandtl number is adopted to describe the turbulent heat transfer and flow of LBE under different heat flux and flow conditions. The average cooling heat flux of 5 × 105 W/m2, the flow inlet temperature of 723.15 K and the flow velocity of 1–3.5 m/s are used in these studies. The heat transfer entropy generation rate is far larger than frictional entropy generation rate, and the heat transfer entropy generation rate distributes more widely than frictional entropy generation over the flow cross-section. Under the same heat transfer area and heat load conditions, the thermodynamic performance of the LBE flow under considered conditions is the best under a slight increase of the absolute heat flux along flow direction condition, followed by the constant heat flux condition; the decreasing absolute heat flux along flow direction is the worst.