An experimental Study on Flow Boiling Pressure Drop Inside Horizontal Tubes with Superhydrophobic and Superhydrophilic wire coil inserts

Superhydrophilic and superhydrophobic surfaces, as one of the new surface engineering methods, are also effective in pressure drop, especially for two phase flows. Therefore, in this research, pressure drop of boiling will be investigated experimentally for R۱۳۴a flow as refrigerant in horizontal tube with uncoated, superhydrophilic and superhydrophobic wire-coils inserted. In this experimental research, a copper tube with inner diameter of ۱۱.۳ mm and wire-coils made of aluminum with thicknesses of ۱ and ۱.۵ mm and pitch ratios to the inner diameter of the tube of ۱ have been used. The mass velocities are ۶۰ and ۸۰ kg/m۲s, and the experiments were performed under a constant heat flux of ۴.۱ kW/m۲. Also the tests have been performed in an average vapor quality between ۰.۱ and ۰.۹. Compare to uncoated aluminum wire-coils, pressure drop of boiling flow has decreased up to ۱۶% by using superhydrophobic wire-coils and has increased up to ۷% by using superhydrophilic wire-coils.

کلیدواژه ها:

Pressure drop ، nano-engineered surfaces ، wire-coils ، superhydrophobic ، superhydrophilic