Taking the mechanical seal of the submersible as the object, a transient coupled heat transfer model was established, and the deformation of the seal face under stable and alternating conditions was investigated by considering the thermal–mechanical coupling effect. The deformation characteristics of the seal face under two different alternative forms of amplitude and period were analyzed. The morphology and wear characteristics of the seal face were measured and discussed based on the pseudo-real test of the mechanical seal under alternating loads. The results showed that the seal face tended to be squeezed near the inner diameter and a tapered convergent gap appeared at the outer diameter of the seal face under alternating loads. The deformation of the seal face presented obvious alternating transient characteristics under alternating loads, and the deformation under alternating rotational speed was greater than that of alternating medium pressure. The deformation of the seal face increased with the amplitude of the alternating loads, while the period of the alternating loads had little influence on it. The wear mechanism of the seal face under alternating conditions was mainly abrasive wear, and the wear caused by alternating rotational speed is more significant. Abstract Taking the mechanical seal of the submersible as the object, a transient coupled heat transfer model was established, and the deformation of the seal face under stable and alternating conditions was investigated by considering the thermal–mechanical coupling effect. The deformation characteristics of the seal face under two different alternative forms of amplitude and period were analyzed. The morphology and wear characteristics of the seal face were measured and discussed based on the pseudo-real test of the mechanical seal under alternating loads. The results showed that the seal face tended to be squeezed near the inner diameter and a tapered convergent gap appeared at the outer diameter of the seal face under alternating loads. The deformation of the seal face presented obvious alternating transient characteristics under alternating loads, and the deformation under alternating rotational speed was greater than that of alternating medium pressure. The deformation of the seal face increased with the amplitude of the alternating loads, while the period of the alternating loads had little influence on it. The wear mechanism of the seal face under alternating conditions was mainly abrasive wear, and the wear caused by alternating rotational speed is more significant. Keywords: mechanical seal; thermal–mechanical coupling; deformation characteristics; alternating load Abstract Taking the mechanical seal of the submersible as the object, a transient coupled heat transfer model was established, and the deformation of the seal face under stable and alternating conditions was investigated by considering the thermal–mechanical coupling effect. The deformation characteristics of the seal face under two different alternative forms of amplitude and period were analyzed. The morphology and wear characteristics of the seal face were measured and discussed based on the pseudo-real test of the mechanical seal under alternating loads. The results showed that the seal face tended to be squeezed near the inner diameter and a tapered convergent gap appeared at the outer diameter of the seal face under alternating loads. The deformation of the seal face presented obvious alternating transient characteristics under alternating loads, and the deformation under alternating rotational speed was greater than that of alternating medium pressure. The deformation of the seal face increased with the amplitude of the alternating loads, while the period of the alternating loads had little influence on it. The wear mechanism of the seal face under alternating conditions was mainly abrasive wear, and the wear caused by alternating rotational speed is more significant. Keywords: mechanical seal; thermal–mechanical coupling; deformation characteristics; alternating load Abstract Taking the mechanical seal of the submersible as the object, a transient coupled heat transfer model was established, and the deformation of the seal face under stable and alternating conditions was investigated by considering the thermal–mechanical coupling effect. The deformation characteristics of the seal face under two different alternative forms of amplitude and period were analyzed. The morphology and wear characteristics of the seal face were measured and discussed based on the pseudo-real test of the mechanical seal under alternating loads. The results showed that the seal face tended to be squeezed near the inner diameter and a tapered convergent gap appeared at the outer diameter of the seal face under alternating loads. The deformation of the seal face presented obvious alternating transient characteristics under alternating loads, and the deformation under alternating rotational speed was greater than that of alternating medium pressure. The deformation of the seal face increased with the amplitude of the alternating loads, while the period of the alternating loads had little influence on it. The wear mechanism of the seal face under alternating conditions was mainly abrasive wear, and the wear caused by alternating rotational speed is more significant. Keywords: mechanical seal; thermal–mechanical coupling; deformation characteristics; alternating load Taking the mechanical seal of the submersible as the object, a transient coupled heat transfer model was established, and the deformation of the seal face under stable and alternating conditions was investigated by considering the thermal–mechanical coupling effect. The deformation characteristics of the seal face under two different alternative forms of amplitude and period were analyzed. The morphology and wear characteristics of the seal face were measured and discussed based on the pseudo-real test of the mechanical seal under alternating loads. The results showed that the seal face tended to be squeezed near the inner diameter and a tapered convergent gap appeared at the outer diameter of the seal face under alternating loads. The deformation of the seal face presented obvious alternating transient characteristics under alternating loads, and the deformation under alternating rotational speed was greater than that of alternating medium pressure. The deformation of the seal face increased with the amplitude of the alternating loads, while the period of the alternating loads had little influence on it. The wear mechanism of the seal face under alternating conditions was mainly abrasive wear, and the wear caused by alternating rotational speed is more significant. Keywords: mechanical seal; thermal–mechanical coupling; deformation characteristics; alternating load Keywords: mechanical seal; thermal–mechanical coupling; deformation characteristics; alternating load Keywords: