Some methods for minimizing erosion-corrosion include improving the flow lines within the pipe by deburring (i.e. - smoothing out irregularities), allowing bends to have larger angles, and changing pipe diameters gradually rather than abruptly. Other methods include slowing the flow rate (minimizing turbulence), reducing the amount of dissolved oxygen, changing the pH, and switching the pipe material to a different metal or alloy.
In addition to the fluid path material used, it is also important to consider your fluid's temperature. At higher temperatures, flow rates should be lowered to minimize erosion-corrosion. For example, as a general rule, water flow velocities should not exceed 8 ft/sec for cold water and 5 ft/sec for hot water (up to approximately 140 °F). In systems where water temperatures routinely exceed 140 °F, flow velocities should not exceed 3 ft/sec. For maximum recommended water velocities in other typical tube materials, refer to Table 1. For other fluids, the maximum allowable fluid velocity can be calculated from:
Allowable velocity for given fluid] = [Allowable velocity for water] x [Density of water/density of given liquid] 1/2.
There will always be a trade-off between thermal performance and reliability/longevity in any cooling system. Increasing fluid flow will give you more cooling or performance only up to a point. After that, increased fluid velocities may rapidly begin to erode and corrode the inside metal surface of the tubing. Designers should consider many different factors, such as the ones discussed above, in order to determine the best solution for their application.
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