<p>Elastocaloric heating/cooling utilizing cyclic phase transition of superelastic NiTi shape memory alloys (SMAs) has been through rapid development in the past decade with a record cooling power of 1284 W achieved recently. The elastocaloric devices mostly operate in four-step Brayton thermodynamic cycles with heat transfer between solid NiTi and fluids. However, previous investigation of thermomechanical coupling of NiTi SMAs was often conducted under sinusoidal cyclic loading in static air without heat transfer fluids, showing significant discrepancies with the elastocaloric applications. To fix this gap, experiment and modelling analysis are performed to investigate the temperature evolution of NiTi thin tubes under Brayton loading cycles with and without heat transfer fluids. It is found that the cyclic non-isothermal stress–strain responses and temperature evolutions of NiTi under Brayton cycles are notably different from those under sinusoidal loading cycles due to the incorporation of fast heat transfer between NiTi and fluids. By utilizing a modified lumped analysis, the influence of latent heat release, hysteresis heat dissipation, and heat transfer on the temperature evolution of NiTi during phase transition are revealed. The results indicate that the model can reasonably replicate the experimentally observed temperature evolution, providing analytical tools for understanding and optimizing elastocaloric performance of NiTi in practical cooling/heating applications.</p>