The use of conical Elements in double-pipe heat exchangers has improved performance by creating turbulent flow patterns that disrupt boundary layers and enhance fluid mixing. The conical shape of the Elements promotes radial mixing, reduces axial dispersion, and increases overall heat transfer surface area and fluid residence time, potentially allowing for more compact designs or increased process throughput in industrial applications. In the current novel study, conical Elements are implemented.

Figure 1: Schematic of conical Elements inside double-pipe heat exchanger

Simulation Process

Design Modeler produces the geometry model. It consists of 12 zones in total. Each conical mixer must be placed in an independent zone to employ a multizone mesh grid, considering the structured grid in pipes. The cross design of the heat exchanger lets 297K of air pass through one side and 338K of hot water from the other side.

Post-processing

The temperature and velocity contours reveal the effects of the stationary conical Elements on heat transfer and fluid flow in the double-pipe heat exchanger. The temperature gradient gradually increases from blue (297K) at the inlet to green-yellow (around 325.8K) at the outlet for the inner fluid, likely air. The outer fluid, water, maintains a relatively constant high temperature (red, 338K) throughout. The velocity contour indicates flow disturbances caused by the Elements, with higher velocities (green-yellow regions) near the mixer surfaces and lower velocities (blue) in the bulk flow. These flow patterns suggest enhanced mixing and heat transfer due to the conical elements despite them being stationary. The overall temperature change from inlet to outlet (297K to 325.8K for air, 338K to 337K for water) indicates an effective heat exchanger.