A Comparison of Simplified One-Dimensional and Two-Dimensional Analytical Models for Predicting Metallic Recuperator Performance

Abstract

The performance models for high-temperature metallic recuperators considering one and two-dimensional heat transfer are presented. In one-dimensional model, an explicit expression to represent the effect of both the temperature and product of partial pressure and mean beam length on the emissivity is developed using emissivity charts. The effect of upstream and downstream surroundings is neglected. A two-dimensional heat transfer model is developed using zone method along with sum-of-gray-gases approximation to study the effect of upstream and downstream surroundings on performance. The results from the two models are compared. For lower values of inlet flue gas temperatures and higher mass flow rates, one-dimensional model predicts results within 5% of two-dimensional model. One-dimensional model provides a simplified solution for the assessment of recuperator performance but predicts the surface temperature distribution on a relatively lower side for higher inlet flue gas temperatures and low mass flow rates.