抄録
This paper presents the numerical study of the turbulent flow and heat transfer in the round tubes equipped with multi-channel twisted tapes (MC-TT). A finite volume method with the RNG k-ε turbulence model was applied for the simulation. The effects of the twist ratio (defined as a ratio of twist length to tape width: y/w = 1.5, 2.0, 3.0, and 4.0) and number of channels (N = 2 and 4) on the fluid flow and heat transfer characteristics were investigated in a turbulent flow regime (5000≤Re≤15000). The computations show that the circular tubes with multi-channel twisted tapes give higher heat transfer rate than the plain tube by around 22-30%. Heat transfer enhancement by the multi-channel twisted tapes is strongly dependent on twist ratio (y/w) and number of channel (N). For the present study, the tape with N = 2 with twist ratio, y/w= 3.0 offers the best heat transfer enhancement with the maximum thermal performance factor of 1.02.
