A Review of CFD Applications in Spiral and Helical Heat Exchangers

Abstract

Spiral and helical heat exchangers are compact thermal devices widely used in process
industries, power generation, and thermal management because their curved passages induce secondary
motions that enhance mixing and convective heat transfer. Over the past two decades, computational fluid
dynamics (CFD) has become a principal tool for analyzing these configurations, enabling detailed access
to local flow structures, temperature fields, and pressure losses beyond the reach of conventional
measurements. Nevertheless, the CFD literature on spiral and helical heat exchangers remains
fragmented: reported Nusselt numbers and pressure drops can differ substantially across studies due to
variability in geometry definition, mesh resolution and near-wall treatment, turbulence closure, numerical
schemes, and the completeness of verification/validation procedures. This review exclusively synthesizes
CFD-based investigations of spiral and helical heat exchangers, considering experimental results only
when used for numerical validation. The selected studies are clustered by exchanger type (helical vs.
spiral), numerical approach (steady vs. transient), turbulence/closure strategy, and research objective
(parametric analysis, enhancement techniques, optimization, and advanced modeling). The review
provides a critical assessment of dominant modeling choices—particularly the prevalence of steady-state
RANS simulations—and identifies recurring methodological weaknesses, including insufficient reporting
of y⁺ and grid convergence, limited turbulence-model sensitivity studies, and validation mostly restricted
to global performance metrics. Finally, key research gaps are articulated, including the scarcity of
transient and scale-resolving simulations, limited non-Newtonian and conjugate heat transfer
formulations, and underrepresentation of spiral heat exchangers in high-fidelity CFD studies. The
synthesis is intended to guide robust CFD workflows and to support future research toward predictive,
reproducible numerical design of curved heat exchanger systems.