Hydrothermal assessment of a double-pass shell and tube heat exchanger in the presence of blade turbulators with different configurations

Abstract

Heat exchangers (HE) are one of the vital heat transfer equipment that have various applications in disparate industries. In this regard, countless methods have been implemented to increase and optimize the heat transfer process inside them. However, passive techniques have received more attention due to the absence of external power consumption. In this study, the impact of employing turbulators with various geometries on the overall heat transfer coefficient (HTC), flow pressure drop (PD), and temperature distribution in the shell-and-tube heat exchanger (STHE) has been computationally investigated. Moreover, for a better examination, the effect of variation of the middle diameter of the turbulator on the hydrothermal behavior of the STHE has been scrutinized. To this end, a 1–2 STHE equipped with five baffles on the shell side and turbulators with different configurations inside the tube is considered. The simulation process is carried out with a variable mass flow rate of 0.2–0.565 kg/s on the tube side and a constant mass flow rate of 1.1 kg/s on the shell side. The outcomes disclosed that the single and double-blade turbulators (SBT and DBT) heighten the HTC and PD inside the STHE tubes. For instance, in the mass flow rate of 0.338 kg/s, the HTC ameliorates by 25.41 % and 33.43 % in the presence of SBT and DBT, respectively. Also, for the mass flow rate of 0.45 kg/s, the PDs for the mentioned turbulators increase by 6.32 and 8.62 times, orderly, compared to the base model (HE without turbulator). Additionally, by increasing the middle diameter of the DBT in a constant value of mass flow rate, the HTC and PD increase. In a mass flow rate of 0.338 kg/s, the HTC of DBT with a 4 mm diameter reduces by 1.97 %, and turbulators with a 6 mm diameter improve by 1.96 %, compared to cases with no variations (5 mm). Furthermore, for the mass flow rate equal to 0.45 kg/s, the turbulator with a 4 mm diameter decreases the PD by 13.8 %, and the turbulator with a 6 mm diameter increases it by 17.4 %, in comparison to the turbulator with a 5 mm diameter (without variation).

Keywords

• Double-pass shell and tube heat exchanger
• Blade turbulators
• Heat transfer enhancement
• Pressure drop