Numerical Analysis and Leakage Investigation of Heat Exchanger Piping Flange Joints under Thermal and Internal Pressure Loads

Flange joint leakage in piping systems and heat exchangers is a persistent challenge in oil, gas, and petrochemical industries, often leading to environmental hazards, operational shutdowns, and significant economic losses. While standard design codes such as ASME Section VIII Division ۱ provide guidelines for bolt sizing, leakage frequently occurs due to complex interactions between internal pressure, thermal expansion, and gasket relaxation. This paper investigates the primary causes of leakage in raised-face flange joints under combined thermal and internal pressure loads. A comprehensive literature review of ۱۰ significant studies (both English and Persian) is conducted to categorize research methodologies. Subsequently, an analytical model based on ASME methodology is developed using MATLAB software to evaluate joint rigidity and sealing performance. The study specifically analyzes the effect of operating temperature (۱۵۰°C) and pressure (۲ MPa) on bolt tension. Results demonstrate that relying solely on the minimum required bolt load (W) calculated by the code is insufficient for preventing leakage under thermal fluctuations. The MATLAB analysis suggests that increasing the assembly bolt load by ۳۰-۴۰% above the code minimum significantly enhances leak tightness without yielding the bolts.

کلیدواژه ها:

Flange Leakage ، ASME Code ، Piping Joints ، MATLAB Analysis ، Bolt Preload ، Sealing Integrity