Simultaneous Measurements of Velocity and Temperature in Nonisothermal Flows

A two-wire probe technique has been developed for the simultaneous and continuous measurements of instantaneous velocity and temperature in nonisothermal flows. The equations of the thermal equilibrium of two adjacent fine wires, one hot and one only a little above the fluid temperature, are solved by employing analog technique, wherein not only the difference of the heat transfer coefficients between two wires but also their variations with both the velocity and temperature are taken into consideration. The measuring system proposed in this study is founded on fairly strict principles of analysis and, hence, provides automatic compensation even for very large amplitude velocity and temperature fluctuations over a frequency range of d-c to six kHz.