The study of radiative base heating from rocket exhaust plumes has attracted considerable attention in the last decades, since the base plane must be protected against thermal solicitations. In particular, with the advent of aluminized propellants and energetic binders, radiative base heating has an increased relevance in the modern solid rocket motors. The use of sophisticated radiation models coupled with accurate CFD simulations requires a great computational effort, which is often not convenient for industrial applications. Therefore, approximate models, as well as fast and flexible solution methods, are presently required for a preliminary and sufficiently accurate prediction of solid rocket plume base heating. In order to predict the heat radiated by the plume, the knowledge of the flowfield properties and of the chemical composition of the exhaust flow is a fundamental requirement. NASA’s SCIPPY&BOAT code is used for the computation of the steady, two-dimensional, axisymmetric fluid dynamic and chemical composition maps of the plume flowfield. A radiation code named PLUME-RAD is developed for the computation of the axisymmetric radial distribution of the radiative heat flux reaching the rocket base plane. The code is based on the numerical integration of the radiative transfer equation for a gray, non-scattering, homogeneous medium via the Discrete Transfer Method. The radiative properties of the gaseous and condensed species that are involved in the process are approximated by means of models available in the literature. Results are presented and discussed for the test case of Vega launcher’s P80 motor flying at zero altitude. They show the main features of the different tools and are in agreement with the expected phenomenology.
Lo studio del surriscaldamento della superficie di coda dei motori a razzo per irraggiamento da parte del getto ha attratto notevole attenzione negli ultimi decenni, poichè tale piano deve essere opportunamente protetto dalle sollecitazioni termiche. In particolare, con l’avvento di propellenti alluminizzati e leganti energetici, questo fenomeno ha acquisito una maggiore rilevanza nei moderni motori a propellente solido. L’uso di sofisticati modelli d’irraggiamento insieme ad accurate simulazioni CFD richiede un grande costo computazionale, che spesso non risulta conveniente nelle applicazioni industriali. Di conseguenza, sono necessari modelli approssimati e metodi di soluzione veloci e flessibili che possano essere applicati per una previsione preliminare e sufficientemente accurata del riscaldamento per irraggiamento del piano di coda dei motori a razzo a propellente solido. Al fine di calcolare il calore irraggiato dal getto, un requisito fondamentale è costituito dalla conoscenza delle proprietà fluidodinamiche e chimiche del flusso. Il codice SCIPPY&BOAT della NASA viene usato per il calcolo delle mappe stazionarie, bi-dimensionali, assialsimmetriche delle variabili fluidodinamiche e chimiche. Un codice denominato PLUME-RAD è sviluppato per il calcolo della distribuzione radiale assialsimmetrica del flusso di calore iraggiato verso il piano di coda del razzo. Il codice si basa sull’integrazione numerica dell’equazione dell’irraggiamento per gas grigi, omogenei e privi di scattering attraverso il Discrete Transfer Method. Le proprietà ottiche dei gas e delle specie condensate che partecipano al processo sono approssimate per mezzo di modelli disponibili in letteratura. Vengono presentati e discussi i risultati ottenuti per il caso test del motore P80 del lanciatore Vega in volo a quota zero. Essi dimostrano le caratteristiche principali dei codici utilizzati e sono in buon accordo con la fenomenologia attesa.
Numerical analysis of solid rocket motor plume radiative heat transfer at low altitude
MARIGLIANI, LEONARDO
2016/2017
Abstract
The study of radiative base heating from rocket exhaust plumes has attracted considerable attention in the last decades, since the base plane must be protected against thermal solicitations. In particular, with the advent of aluminized propellants and energetic binders, radiative base heating has an increased relevance in the modern solid rocket motors. The use of sophisticated radiation models coupled with accurate CFD simulations requires a great computational effort, which is often not convenient for industrial applications. Therefore, approximate models, as well as fast and flexible solution methods, are presently required for a preliminary and sufficiently accurate prediction of solid rocket plume base heating. In order to predict the heat radiated by the plume, the knowledge of the flowfield properties and of the chemical composition of the exhaust flow is a fundamental requirement. NASA’s SCIPPY&BOAT code is used for the computation of the steady, two-dimensional, axisymmetric fluid dynamic and chemical composition maps of the plume flowfield. A radiation code named PLUME-RAD is developed for the computation of the axisymmetric radial distribution of the radiative heat flux reaching the rocket base plane. The code is based on the numerical integration of the radiative transfer equation for a gray, non-scattering, homogeneous medium via the Discrete Transfer Method. The radiative properties of the gaseous and condensed species that are involved in the process are approximated by means of models available in the literature. Results are presented and discussed for the test case of Vega launcher’s P80 motor flying at zero altitude. They show the main features of the different tools and are in agreement with the expected phenomenology.File | Dimensione | Formato | |
---|---|---|---|
TESI_LeonardoMarigliani_05_04.pdf
accessibile in internet per tutti
Descrizione: Testo completo della Tesi in PDF
Dimensione
3.33 MB
Formato
Adobe PDF
|
3.33 MB | Adobe PDF | Visualizza/Apri |
I documenti in POLITesi sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
https://hdl.handle.net/10589/134063