In this manuscript, heat transfer at the speed of sound has been established by introduction of a local form of the second law of thermodynamics and conservation laws and validated by experimental data. When the local form, excess entropy, equals to zero, the boundary of the second law is reached and superfluidity and sound are observed; otherwise, motion is dissipative. First and second sound are generated in super momentum and super energy flows, respectively. From differential equations of conservation, wave equations, speed of sound, and impedance and thermal resistance of first and second sound are derived. Dependent on conventional thermomechanical properties, a formula of second sound is obtained, which has not been found in public domain. The theory and formulas of sonic heat transfer and interface thermal resistance and conductance are derived according to the principles of acoustics first time. We validated the speed of second sound and formulas for for heat transfer at sound speed by experimental data. Overall, calculations from formulas capture key characteristics of the experimental data satisfactorily. At lower temperature, the predicted temperature jump at the interface matches data well. Predictions of interface thermal conductance demonstrate all important characteristics and some of them match data well. Temperature discontinuity at an interface is the result of acoustic effect of second sound of two materials. Differential equations of conservation of both regular and super states can be utilized to solve a complex problem computationally.

在这份手稿中，通过引入热力学第二定律和守恒定律的局部形式，建立了声速传热，并通过实验数据进行了验证。当局部形式过剩熵为零时，达到第二定律的边界并观察到超流和声音；否则，运动是耗散的。第一声​​和第二声分别在超动量和超能量流中产生。从守恒的微分方程可以导出波动方程、声速以及第一和第二声音的阻抗和热阻。依赖于传统的热机械特性，获得了第二声音的公式，这在公共领域中是找不到的。首次根据声学原理推导出声波传热和界面热阻、电导的理论和公式。我们通过实验数据验证了第二声速和声速传热公式。总的来说，公式计算令人满意地捕捉了实验数据的关键特征。在较低温度下，界面处预测的温度跳跃与数据匹配良好。界面热导率的预测展示了所有重要特征，其中一些与数据匹配良好。界面处的温度不连续性是两种材料的第二声的声学效应的结果。正则态和超态守恒的微分方程可用于解决复杂的计算问题。