VALIDATION OF NUMERICAL MODELS FOR PREDICTION OF PRESSURE DROP IN HIGH CAPACITY LONG DISTANCE LIGNITE FLY ASH PNEUMATIC CONVEYING

This paper will validate two basic concepts of numerical models for prediction of pressure change along the transport pipeline in the case of long distance and high capacity lignite ash pneumatic conveying. Application of various friction factor correlations and variation of given parameter, led to the total of fourteen different numerical models and program codes in FORTRAN. The input data for numerical models are based on comprehensive experimental research of high ca-pacity and long distance Kolubara lignite fly ash pneumatic conveying system within 620 MWe thermal power plant unit under operating conditions. Numerical simulation results are validated against experimental data and subjected to sta-tistical analysis methods. The functional dependence obtained by the least squares method was evaluated using mean squared deviation and correlation ra-tio. The predicted pressure changes show the best agreement, with the measured decrease of pressure amplitudes along the transport pipelines, for the model based on the momentum balance of air-ash mixture flow and friction factor cor-relation given by Dogin and Lebedev for the parameter A = 1.4 center dot 10-6. This model achieved the best correlation ratio of 93.99% for Pipeline 1 and 91.33% for Pipeline 2, as well as the best mean squared deviation of 9.58% for Pipeline 1 and 13.66% for Pipeline 2. Also, the fanning friction factor values are fully con-sistent with previously examined cases available in the literature. Numerical sim-ulation model can be used for prediction of the ash pneumatic conveying capacity and pressure drop for the specified transport pipeline.