Preliminary Estimation of Channel Deformation and Heat Transfer Performance in a Printed Circuit Heat Exchanger

Printed Circuit Heat Exchangers (PCHEs) are widely used for industry application, such as cryogenic storages, evaporators and reactors. A PCHE has strength in high temperature and high pressure operating conditions. Therefore, A PCHE is considered as a candidate intermediate heat exchanger type for a high temperature gas cooled reactor (HTGR). PCHE design and manufacturing processes are well established for using stainless steel materials. The uncertainties from design and manufacturing processes are allowable for normal industrial applications using stainless steel because design margin is mostly enough. A channel is usually assumed as semicircle in the design stage but the product is not perfect semicircle after chemical etching and diffusion bonding. The deformed channels may increase the pressure difference and decrease the heat transfer performance. These uncertainties may reduce the design margin and the life time of the PCHE. The effect of longitudinal heat conduction is one of the design uncertainties when a simple LMTD method is used. The estimation of channel deformation during manufacturing process is required in terms of engineering. Ni-based alloy is used for the extreme applications. Channel deformation and heat transfer performance are preliminarily estimated in the present study. A PCHE channel usually is design to semicircle shape. We ordered PCHE with 1.5 mm in diameter but the product was 1.72 mm in diameter. A careful quality assurance is required for high temperature and high pressure application.