[Background] Bending of heat pipes is an inevitable occurrence in heat pipe cooled reactors designed for shadow cone shielding and the reduction of neutron leakage. Geyser boiling

characterized by periodic fluctuations in wall temperature during heat pipe operation

is common in conventional straight heat pipes. Temperature fluctuations in straight heat pipes can reach up to hundreds of degrees Celsius

which has an adverse impact on the heat transfer performance and stable operation of heat pipes. [Purpose] This study employs both experimental and numerical methods to analyze the impact of high-temperature sodium heat pipe bending on heat transfer performance. [Methods] An experimental platform was established to conduct comparative tests on straight and bent heat pipes under vertical conditions. The heat pipes were heated by electromagnetic induction heating and cooled by natural convection and radiation. The wall temperatures of the straight heat pipe and bent heat pipe were compared to analyze the effect of bending on geyser boiling phenomena. Meanwhile

a multiphase flow model was established using Fluent to simulate the internal flow within both straight and bent heat pipes. [Results] The experimental results indicate that

under identical operating conditions

the bent heat pipe exhibits significantly lower temperature fluctuation amplitude and period during geyser boiling compared to the straight heat pipe. The simulation results reveal that the presence of the bend induces a stable stratified flow regime

replacing the slug flow typically observed in straight pipes

thus mitigating the effects of geyser boiling. The maximum wall temperature decreases by 15℃ in bending heat pipe. [Conclusions] In conclusion

this research comprehensively investigated the impact of heat pipe bending on geyser boiling phenomena through both experimental and numerical approaches. The findings demonstrate that bending the high temperature sodium heat pipe can effectively suppress geyser boiling

which is beneficial for enhancing the heat transfer performance and operational stability of heat pipe cooled reactors.