A type of swirl nozzle

i.e.

a threaded hole nozzle with four spiral grooves on the diameter of the hole was proposed. The heat transfer characteristics of the three kinds of swirl nozzles (insert

built-in torsion belt and guide vane) with the helical hole nozzle at the same helix angle when the Reynolds numbers were 6000

12000 were investigated. The pressure and flow coefficient of the air supply chamber corresponding to each nozzle were analyzed. The experimental results showed that the spiral hole nozzle had a high heat transfer efficiency in the central area of the target surface

and the stagnation Nusselt number was 29.7%-43.3% higher than the other three nozzles. When the jet space was limited (semi-enclosed space)

the Nusselt number of dropped down by 40% to 60%

and the built-in plug nozzles had the largest drop. In addition

the four kinds of swirl nozzles had the largest air supply chamber pressure of the built-in plug nozzle

one order of magnitude higher than the smallest screw hole nozzle. The analysis of the pressure loss coefficient showed that the pressure loss coefficient of the nozzle hole was the smallest

only about 1/4 of the built-in plug nozzle

the Reynolds number was doubled

and the pressure loss coefficient of the built-in plug nozzle dropped by 14% on average.