Mathematical Modeling of Criteria Weighting and Risk Priority by Using Deviation Value Step-Wise in Energy Analysis for Double-Pipe Heat Exchangers

Failure Mode and Effects Analysis (FMEA) is utilized for risk appraisal in various domains. In the FMEA methodology, each failure mode is evaluated by considering three risk factors: severity (S), occurrence (O), and detection (D). Subsequently, the Risk Priority Number (RPN) is obtained by multiplying these listed factors. This study introduces the Deviation Value Step-Wise Method (DVSM) as a new mathematical model for determining the scores of the SOD factors. This methodology consists of three main steps. Firstly, the FMEA technique is used to identify failure modes. Then, the DVSM is employed to assign weights to the SOD components. In this step, relative importance is determined based on linguistic variables. The third step involves ranking failure modes using the weighted RPN. Two general examples and a case study of two-pipe heat exchanger failure modes are considered to validate the proposed model and test the obtained results. The results demonstrate that the suggested approach has enhanced the overall prioritization of failure modes. This enables the Decision-Maker (DM) to identify primary failure modes and formulate corrective/preventive actions. Finally, both sensitivity analysis and energy efficiency investigation have been performed.