Dependence of speed of sound on salinity and temperature in concentrated NaCl solutions

An ultrasonic velocimeter for salinity measurements in a solar pond has been developed and tested. Calibration of the probe is accomplished by comparing speed of sound measurements in distilled water with accepted values. Speed of sound in NaCl solutions with salinities from 0%–21% by weight has been measured over a temperature range of 7°–88°C. An equation has been developed to compute salinity from the measured speed of sound and the temperature for NaCl solutions. Accuracies better than 0.2% by weight have been demonstrated. The method shows good potential for in situ salinity measurements in salt-gradient solar ponds.