Experimental investigation on heat transfer characteristics of flow boiling in zigzag channels of printed circuit heat exchangers

Abstract

To optimize printed circuit heat exchangers, the experimental heat transfer characteristics of two-phase flow boiling in zigzag channels of PCHE were investigated. The experimental conditions cover mass fluxes of 100~400 kg /(m²•s), vapor qualities of 0.1~1.0, heat fluxes of 1.5~12.5 kW/m², and saturation pressures of 0.15~0.35 MPa. The research results show that, the heat transfer coefficient initially increases and then decreases as the vapor quality increases, representing a maximum at vapor quality of 0.85~0.9; as the heat flux increases, the heat transfer coefficient increases at a vapor quality < 0.35; the critical conditions of slug-annular transition and annular-dryout transition are corresponding to the void fractions of 0.96 and 0.994; as the saturation pressure decreases from 0.35 to 0.15 MPa, the heat transfer coefficient is intensified by 16.7%. A new correlation of two-phase heat transfer coefficients for flow boiling in zigzag channels was developed with a deviation within ±25%.