Recuperator Performance Assessment in Humidified Micro Gas Turbine Applications Using Experimental Data Extended with Preliminary Support Vector Regression Model Analysis

Although the positive impact of cycle humidification on the performance of micro Gas Turbines (mGTs) has already been proven numerically and experimentally, very detailed modeling of the system performance remains challenging, especially the determination of the recuperator effectiveness, which has the highest impact on the final cycle performance. Indeed, the recuperator performance depends strongly on the mass flow rate of the air stream and its humidification level, two parameters that are difficult to measure accurately. Accurate modeling of the recuperator performance under both dry and humidified conditions is thus essential for correct assessment of the potential of humidified mGT cycles.

In this paper, we present a detailed analysis of the recuperator performance under humidified conditions using averaged experimental data, extended with the application of a Support Vector Regression (SVR) on a time series to improve noise-modeling of the output signal, and thus enhance the accuracy of the monitoring process. In a first step, the missing experimental parameters were obtained indirectly, using experimental data in combination with the compressor map. Despite the low accuracy, some general trends could be observed, indicating that the recuperator, despite having an increased total exchanged heat flux, is too small to exploit the full potential of the humidification. In a second step, by means of the SVR model, a first attempt was made to improve the accuracy and reduce the scatter on the recuperator performance determination. The predicted results with the SVR indicated indeed a reduced scatter, opening a pathway towards online recuperator performance prediction.