Except for the excellent mechanical performance,metal honeycomb can also be regarded as the heat exchanger because of high areal density.Intuitively,the heat transfer performance of metal honeycomb heat exchanger(MHHE)can be further enhanced by adjusting the graded distribution of pore sizes,which had also been proved by the graded design based on the simplified analytical methods.In these methods,the cross-sectional fluid temperature distribution of cooling fluid was neglected and the assumption of Constant Cross-sectional Fluid Temperature(CCFT)was adopted.However,the recent numerical study indicated that the CCFT based analytical methods may lead to a large error in estimating the heat transfer performance of the graded MHHE.Thus,it is necessary to examine the effectiveness of the basic assumptions for the simplified analytical methods.