回程托辊卡死是导致带式输送机火灾的主要原因之一。为研究带式输送机回程托辊卡死故障摩擦升温特性，采用平台实验与数值模拟相结合的方法，研究了输送带速度、巷道风速和环境温度对卡死回程托辊温度的影响，结果表明：卡死回程托辊温度随环境温度和输送带速度的增加而显著升高，温度达到稳态的时间延长；巷道风速的提高有效降低了卡死回程托辊温度并缩短了温度达到稳态的时间。考虑到输送带磨穿卡死的回程托辊导致托辊内部煤粉积聚并引发火灾的情况，进一步研究了输送带速度、巷道风速、环境温度及卡死回程托辊内煤粉积存比例（煤粉在托辊内部积存体积与托辊可容纳煤粉最大体积之比）对煤粉最高温度的影响，结果表明：输送带速度、巷道风速和环境温度对卡死回程托辊内煤粉最高温度的影响，与对卡死回程托辊温度的影响规律一致；卡死回程托辊内煤粉积存比例的增加会加剧煤粉温度的升高；在环境温度为20 ℃、输送带速度为3.5 m/s、巷道风速为1 m/s、100%煤粉积存比例的工况下，煤粉最高温度达87.5 ℃，较25%煤粉积存比例时升高了43.2 ℃，高于中低阶煤的自燃临界温度，火灾风险显著增加。

Seized return idlers are one of the main causes of fire in belt conveyors. To investigate the frictional heating characteristics of seized return idlers in belt conveyors, a combination of platform experiments and numerical simulations was used to study the effects of conveyor belt speed, roadway airflow velocity, and ambient temperature on the temperature of the seized return idlers. The results indicated that the temperature of the seized return idler increased significantly with the rise in ambient temperature and conveyor belt speed, and the time required to reach thermal equilibrium was prolonged. An increase in roadway airflow velocity effectively reduced the temperature of the seized return idlers and shortened the time to reach thermal equilibrium. To further assess the fire risk from coal dust accumulation within stuck rollers due to belt wear, the study explored the effects of conveyor belt speed, roadway airflow velocity, ambient temperature, and coal dust accumulation ratio in the seized return idlers (defined as the ratio of accumulated coal dust volume to the maximum capacity of coal dust volume in the idlers) on the maximum temperature of the coal dust. The results revealed that the effects of conveyor belt speed, roadway airflow velocity, and ambient temperature on the maximum temperature of coal dust in the seized return idlers were consistent with their effects on seized roller temperature. Additionally, an increase in the coal dust accumulation ratios in the seized return idlers resulted in a more significant rise in coal dust temperature. Under conditions of an ambient temperature of 20 °C, conveyor belt speed of 3.5 m/s, roadway airflow velocity of 1 m/s, and a 100% coal dust accumulation ratio, the maximum temperature of coal dust reached 87.5°C, which was 43.2 °C higher than that at a 25% accumulation ratio. This temperature exceeded the threshold value of spontaneous combustion for low- to medium-grade coal, indicating a substantial increase in fire risk.