Numerical simulation of multiphase flow around suction plates of ventilation mill in the function of extending its remaining working life

Ovaj rad prestavlja mogućnost korišćenja rezltata numeričkih simulacija, za smanjenje habanja radnih delova ventilacionog mlina za mlevenje uglja u termoelektrani Kostolac B. Mogućnost revitalizacije usisnih ploča ventilacionog mlina je zasnovan na 3D numeričkoj simulaciji multifaznog strujanja u ventilacionom mlinu. Čvrste čestice smeše ugalj, mineralne materije, pesak tokom procesa mlevenja izazivaju veliko habanje usisnih ploča. Primenom softverskog paketa ANSYS FLUENT 12, dobiće se detaljniji prikaz multifaznog strujanja i brzine mešavine koja omogućuje da se na osnovu intenziteta i smera brzine, preciznije odrede kritične zone u kojima će se pojaviti oštećenja kod usisnih ploča ventilacionog mlina. Korišćen je Euler-Euler model mešavine. Rezultati dobijeni pomoću numeričke simulacije koristiće se za izbor optimalne tehnologije revitalizacije usisnih ploča ventilacionog mlina. Primenom ovog pristupa rešavanja problema smanjio bi se broj mogućih interventnih popravki i produžio bi se period između neophodnih kompletnih remonta postrojenja, čime bi se ostvarili značajni ekonomski efekti i ujedno povećala energetska efikasnost termoenergetskih agregata.This paper presents results of the analyses obtained by numerical simulation for the possibilities of increasing the wear resistance of the ventilation mill working parts for coal grinding in the Kostolac B power plant. The possibilities for modification are based on 3D numerical simulation of multiphase flow of ventilation mill. Mineral materials during the process of milling in the ventilation mill cause strong wear of the suction plates. The multiphase flow simulations are performed in order to obtain the mineral materials paths and velocity vectors. The mixture model of the Euler-Euler approach is used. The results obtained in the numerical simulation serve for the selection of an optimal redesign of the suction plates. The application of this approach can reduce the number of possible repairs and extends the period between them, resulting in significant economic effects

Numerical simulation of multiphase flow around suction plates of ventilation mill in the function of extending its remaining working life

Ovaj rad prestavlja mogućnost korišćenja rezltata numeričkih simulacija, za smanjenje habanja radnih delova ventilacionog mlina za mlevenje uglja u termoelektrani Kostolac B. Mogućnost revitalizacije usisnih ploča ventilacionog mlina je zasnovan na 3D numeričkoj simulaciji multifaznog strujanja u ventilacionom mlinu. Čvrste čestice smeše ugalj, mineralne materije, pesak tokom procesa mlevenja izazivaju veliko habanje usisnih ploča. Primenom softverskog paketa ANSYS FLUENT 12, dobiće se detaljniji prikaz multifaznog strujanja i brzine mešavine koja omogućuje da se na osnovu intenziteta i smera brzine, preciznije odrede kritične zone u kojima će se pojaviti oštećenja kod usisnih ploča ventilacionog mlina. Korišćen je Euler-Euler model mešavine. Rezultati dobijeni pomoću numeričke simulacije koristiće se za izbor optimalne tehnologije revitalizacije usisnih ploča ventilacionog mlina. Primenom ovog pristupa rešavanja problema smanjio bi se broj mogućih interventnih popravki i produžio bi se period između neophodnih kompletnih remonta postrojenja, čime bi se ostvarili značajni ekonomski efekti i ujedno povećala energetska efikasnost termoenergetskih agregata.This paper presents results of the analyses obtained by numerical simulation for the possibilities of increasing the wear resistance of the ventilation mill working parts for coal grinding in the Kostolac B power plant. The possibilities for modification are based on 3D numerical simulation of multiphase flow of ventilation mill. Mineral materials during the process of milling in the ventilation mill cause strong wear of the suction plates. The multiphase flow simulations are performed in order to obtain the mineral materials paths and velocity vectors. The mixture model of the Euler-Euler approach is used. The results obtained in the numerical simulation serve for the selection of an optimal redesign of the suction plates. The application of this approach can reduce the number of possible repairs and extends the period between them, resulting in significant economic effects

Wear reducing of ventilation mill suction plates based on the multidisciplinary research

The aim of this paper is to present the investigations of the possibilities of increasing the wear resistance of the ventilation mill parts for coal grinding in power plants, by application of optimum hard coating technologies. High velocity of sand particles in the ventilation mill causes strong wear of the suction plates. The input data for plate modification are based on 3D numerical simulation of multiphase flow in grinding mill. The mixture model of the Euler-Euler approach is used. The results obtained in the numerical simulation serve for the selection of optimum redesign of the suction plates. To improve surface properties, the hard, wear-resistant coatings were created by hardfacing, technologies by manual metal arc and self-protecting flux core electrodes. Before applying hardfaced suction plates in the exploitation conditions, it is necessary to study model hardfaced samples. The experimental tests of redesigned suction plates during the real exploitation conditions show that the proposed technology of hardfacing gives good results. The relative weight loss of the suction plates after 1440 h period of exploitation in real conditions is very small 1-3%. The application of proposed technology can reduce the number of possible repairs and extends the period between them, resulting in significant economic effects