Method for simultaneous determination of thermal conductivity and kinematic viscosity

A heating sensor capable of generating heat and measuring its own temperature is placed in a fluid and a thermometric sensor is placed in the fluid and inside a temperature boundary layer formed around the heating sensor upon heat generation therefrom. A temperature of the heating sensor and a temperature of the fluid are measured. A relationship between thermal conductivity of the fluid and a differential value between the temperature of the heating sensor and the temperature of the fluid is used to determine the thermal conductivity of the fluid. Then, the heating value of the heating sensor is adjustably increased so that the thermometric sensor is positioned outside the temperature boundary layer. A temperature of the heating sensor and the temperature of the fluid are measured. The relationship between kinematic viscosity of the fluid and a differential value between the temperature of the heating sensor and the temperature of the fluid is used to determine the kinematic viscosity of the fluid. Alternatively, a single heating sensor and a pair of the thermometric sensors are used, where one of the thermometric sensors is placed outside the temperature boundary layer, and the other thermometric sensor is placed inside the temperature boundary layer, or a pair of the heating sensors is used with a single thermometric sensor placed outside the temperature boundary layer formed around one of the heating sensors and inside the temperature boundary layer formed around the other heating sensor.