Smulation optimisation of a seven-electrode conductivity cell

In order to improve the measurement performance of the seven-electrode conductivity sensor, this study focuses on the influence of the electrode spacing on the electric field distribution, current density, and polarisation effect, and explores the operating characteristics of the conductivity cell under different voltage electrode spacings through simulation and experimental validation, aiming to find out the optimal electrode spacing, reduce the polarisation effect, and improve the measurement accuracy of the conductivity. In this study, the basic simulation model of a seven-electrode conductivity cell was constructed, and simulations were carried out in seawater with different conductivities by changing the electrode spacing to analyse the effects of electrode spacing on current density, electric field distribution, and polarisation intensity, and the results show that when the spacing is in the range of 2.8 mm to 4.0 mm, the value of the current density is small and basically stable and unchanged, and the value of the current density decreases, which is conducive to the reduction of the polarisation effect and the improve the measurement accuracy. Based on the simulation results, the voltage electrode spacing of 3.8 mm was selected as the optimised electrode spacing, and the effect of the structural optimisation was verified by experimental comparison. The experimental data showed that the optimised seven-electrode conductivity sensor (labelled D3.8mm) reduced its error in measuring conductivity by about 68.6% and 27.9% at 20°C and 5°C, respectively, compared to the unoptimised sevenelectrode conductivity sensor (D2.0mm). This confirms that a reasonable adjustment of the electrode spacing can significantly improve the measurement performance of the sensor. In summary, this study has identified the optimal electrode spacing through simulation optimisation design, which reduces the polarisation effect and improves the measurement accuracy of the conductivity sensor.