Numerical study of effects of vortex generators on heat transfer deterioration of supercritical water upward flow

High‐heat flux flow and heat transfer transitions in a supercritical loop: Numerical verification and correlation

“…The radius of the tube (r) is 5 mm, the length of the heating section (L 1 ) is 4 m with an adiabatic inlet area (L 2 = 0.2 m) which is added to fully develop the flow boundary layer at the inlet to better simulate the heat transfer in the long vertical loop. 35 The experimental system of the supercritical water loop (for comparison) contains a high-pressure circulating pump, flow meters, preheaters, a test section, coolers and circulating water tank, etc. 34 The operating conditions in the loop: pressure 1A.…”

A thermal stress analysis of fluid–structure interaction applied to boiler water wall

“…1,2 There is the conventional single statement of flow refrigerant inside the channel under supercritical pressure operation when the flow in that liquid-vapor transition does not occur. 3 However, because of the harsh environment the material exposed, the failure of the water wall has been found under many circumstances that result to not only the loss of economic but also the hazard of safety operation. [4][5][6] The extensive temperature distinction from the junction area between the perforated and the unperforated filed of the water wall is one of the significant reasons that causes abnormal thermal stress and excessive deformation.…”

“…It is commonly believed that the presence of HTD and the excessive thermal deviation of the vertical water wall, which is regarded as the undesirable phenomenon, have brought about fatigue failure and stress damage in the operation process. 3 Therefore, broad scientific researches paid attention to the materials that are supposed to enhance the capacity of high-temperature resistance. 8,9 In order to understand the crack failure of the furnace channel, there is no denying that the investigation of the thermal stress and strain distribution not only is of paramount importance to avoid such malfunction but also improves the mechanical reliability of the furnace.…”

“…As the key component of the boiler, the furnace water wall absorbs the energy from the fuel chamber flame, which makes the circulating water heated and evaporated into saturated steam 1,2 . There is the conventional single statement of flow refrigerant inside the channel under supercritical pressure operation when the flow in that liquid–vapor transition does not occur 3 . However, because of the harsh environment the material exposed, the failure of the water wall has been found under many circumstances that result to not only the loss of economic but also the hazard of safety operation 4–6 .…”

“…Moreover, the working refrigerant closed to the pseudocritical region establishes an abnormal drastic variation of parameters, leading to the inhomogeneous behavior of heat transfer inside the channels, which is called heat transfer deterioration (HTD). It is commonly believed that the presence of HTD and the excessive thermal deviation of the vertical water wall, which is regarded as the undesirable phenomenon, have brought about fatigue failure and stress damage in the operation process 3 . Therefore, broad scientific researches paid attention to the materials that are supposed to enhance the capacity of high‐temperature resistance 8,9 .…”