Measurement of the temperature and concentration boundary layers from a horizontal rotating cylinder surface

• A specialized minitype thermocouple and a dry-wet bulb thermocouple are designed and manufactured.
• The effects of rotation on the temperature and concentration distributions have been investigated experimentally.
• The influence of rotation on the ascending side is different from that on the descending side.
• The error caused by radiation has been analyzed.

In order to measure the temperature and concentration boundary layers from a large diameter horizontal rotating cylinder surface, a minitype thermocouple and a dry-wet bulb thermocouple have been used in the present study. The effect of rotation on the temperature and concentration distributions has been investigated experimentally. The results indicate that the influence of rotation on the ascending side is different from that on the descending side. With the increase of rotational Reynolds number Rer, the temperature and concentration gradients increase consistently on the ascending side. But on the descending side, the temperature and concentration gradients decrease initially and reach a minimum, then begin to increase with the increase of Rer. The temperature measurement error caused by radiation is less than 3%, while the concentration measurement error caused by radiation ranges from 3% to 8%, and it will get larger when approaching the cylinder surface.