The numerical simulations for helical baffles heat exchanger with different Prandtl number (Pr) fluids and the comparison for helical baffles heat exchangers with different helical tilt angle (beta) were presented in this paper. The results reveal that, the helical baffles are used to direct the shell side fluid flow spirally across the tubes, and the guide function will weaken when large Pr fluids involved. The heat transfer coefficient per unit length pressure drop decreases with the increase of heat exchanger length, and for heat exchangers with same length, the heat transfer coefficient per unit pressure drop increases with the increase of beta. By comparing heat exchangers with same required heat transfer capacity, heat exchanger contained water as the shell side fluid achieves the best heat transfer performance when beta is at 40 degrees, and for shell side fluid with big Pr, the small angle scheme is the optimal selection. (C) 2013 Elsevier Ltd. All rights reserved.