Issues affecting the reliability of dynamic dip testing as a method to assess the condensate drainage behavior from the air-side surface of dehumidifying heat exchangers

In dynamic dip testing, retreating contact angle is the only important factor in surface wettability, whereas contact angle hysteresis is more important in condensing environments.

“(3) In dynamic dip testing, retreating contact angle ( θ R ) is the only important factor in surface wettability, whereas contact angle hys­ teresis ( θ A θ R ) is more important in condensing environments.”

Condensate formation and drainage characteristics are different for dynamic dip testing and wind tunnel testing.

“According to the results of this experiment, condensate formation and drainage characteristics are different for the two experimental test methods.”

Although dynamic dip testing does not provide an accurate prediction of residual water mass, it can be used to rapidly assess the drainage characteristics of heat exchangers.

“Although dynamic dip testing does not provide an accurate prediction of residual water mass, it can be used to rapidly assess the drainage characteristics of heat exchangers.”

When fin pitch is smaller, droplets retained on the fin surface after dynamic dip testing are smaller and not easy to bridge, but in wind tunnel testing, condensation droplets are prone to bridge and are difficult to remove.

“(2) When the fin pitch is smaller, the droplets retained on the fin surface after the dynamic tip testing are smaller and not easy to bridge, but in the wind tunnel testing, condensation droplets are prone to bridge and are difficult to remove;”

In dynamic dip testing, most water is swept away from the fin surface by volume movement, while in wind tunnel testing, water droplets initially form on the fin surface and then move down due to gravity and shear forces.

“(1) In dynamic dip testing, most water is swept away from the fin surface by volume movement, while in wind tunnel testing, the water droplets initially form on the fin surface and then move down due to gravity and shear forces;”