Abstract: With the global decline in net trade volume of pipeline natural gas, the operational deployment of liquefied natural gas （LNG） carriers has been steadily increasing. In particular, inerting constitutes a critical procedure during LNG cargo operation, as it prevents the mixing of natural gas with oxygen and thereby ensures the safety of subsequent loading and unloading procedures. To enhance the efficiency of the inerting process in LNG cargo tanks, numerical simulations were conducted using the commercial software ANSYS Fluent,and a scaled-down physical model of the cargo tank was developed. The study was designed to systematically investigate the influence of the inlet Froude number （Fr）, the temperature difference between the injected nitrogen and the internal air,as well as the pressure inside the tank, and to evaluate their respective impacts on the inerting performance. By analyzing the flow field and oxygen volume fraction contours, the evolution patterns of inerting at different stages were summarized. Subsequently, the convection and concentration-driven diffusive terms were introduced to investigate the characteristic mechanisms governing changes in oxygen volume fraction under various operating conditions. The results indicate that the optimal inlet Fr range for efficient inerting lies between 700 and 1 200. Specifically, when the Fr is maintained close to 1 100, the inerting time can be reduced by 44% and 54% under temperature differences of 15 K and 30 K, respectively, when compared to the isothermal case. Meanwhile, the nitrogen consumption is decreased by 6% and 8%, respectively. Furthermore, variations in internal tank pressure within the range of 0 to 15 kPa result in differences of less than 2% in both inerting time and nitrogen usage. In conclusion, under the premise of ensuring economic efficiency, the inlet nitrogen temperature can be raised to about 30 K or more above the ambient temperature during inerting, while maintaining the inlet Fr number at around 1 100.