A Critical Review: Shape Optimization of Welded Plate Heat Exchangers based on Grey Correlation Theory

•Incorrect design of experiment (DoE) & model hampers the reliability of shape optimization.•The study identifies two standard forms of GRA models.•The appropriateness of DoE for the reliable optimization has been highlighted.•Critical review of the interesting study by Zhicheng et al., is presented along with recommendations. Shape optimization and heat analysis of heat exchangers are important areas of research that are seeking attention among scholars from thermal engineering and related fields since decades. In the 123rd volume of Applied Thermal Engineering a paper entitled “Shape optimization of welded plate heat exchangers based on grey correlation theory” was published. The current study exposed not only the inappropriate execution of Deng’s Grey Relational Analysis model, which is referred to as grey correlational theory in that publication, but also some miscalculations. Problem with the design of the experiment and other issues have also been reported. These mistakes, along with the fact that some crucial data was missing from that publication, make the reproducibility of the certain results in that publication problematic, and are highlighted in the current study. The study is particularly important for industrial heat analysts and the researchers interested in multi-objective optimization through grey methods.