Calculating Air Flow to Cool Manufacturing Processes

IMG_7065
This application needed a way to cool steel plates from 150C to 70C

I’ve written before about using ambient air to cool an application, calculating the required airflow to maintain a temperature.  And, I was recently contacted by an end user in India in need of a way to cool electromagnets in a similar application.

The need was to reduce the temperature of high manganese steel plates (dimensions of 1800mm x 800mm x 500mm) from 150°C to less than 70°C, using air at 40°C.  These steel plates have a specific heat of 0.5107896 J/g°C, weigh 120kg each, and protect the coil and insulation of the electromagnets in this process.  So, just as was the case in previous applications, we started with the process shown below.

heat load calc process
Heat load calculation process

In doing so, we calculated a heat load of 279,245 BTU/hr., which will require an air volume of 1,805 CFM to cool as needed.  (Click the image below for an expanded view of the calculations)

Electromagnet calculations
Heat load calculations

The recommendation to provide this cooling was the use of (6) 120022 Super Air Amplifiers, operated at 80 PSIG and installed along the length of the plates to distribute airflow.  As we can see in the chart below, each 120022 Super Air Amplifier will move an air volume of 341 CFM at the outlet of the unit, making (6) of these units suitable for this application.  And, if we consider entrainment of additional ambient air at distances away from the outlet of the 120022 Super Air Amplifier, we can consider these units may cool the steel faster than the 1 minute cycle time used for calculation purposes.

air amp chart
Super Air Amplifier performance chart

This application is a great example of how an engineered compressed air solution can remove process disturbances effectively, and efficiently solve problems.  If you have a similar application or even one that is entirely different, contact an EXAIR Application Engineer.

Lee Evans
Application Engineer
LeeEvans@EXAIR.com
@EXAIR_LE