Space industry and particularly space propulsion are deeply affected by the growing awareness about the values of ecology and the needs of an environmental friendly technological development. Current state-of-the-art technologies for both liquid and solid propellants employ formulations that produce environmental hazardous and toxic products. In particular, liquid storable combinations for mono- and bi-propellants mainly rely on hydrazine (N2H4) or hydrazine-derived substances, which are proved to have carcinogenic implications. Regarding solid propulsion, the oxidizer in the most common formulations is ammonium perchlorate (AP, NH4ClO4), which is toxic and whose production leads to contamination of groundwater. Moreover, combustion of AP-based propellants produces great amounts of hydrogen chloride (HCl), a substance responsible for acid rains and ozone depletion. Ammonium perchlorate is currently employed in the propellant formulation of solid rocket boosters of the European launcher Ariane 5. In the near future, new European regulations are expected to reduce or even abolish the usage of AP. These considerations clearly highlight the interest in the investigation of materials for so called “green propellants”. One of the most promising substances for a possible application in both liquid and solid green propellants is ammonium dinitramide (ADN, NH4N(NO2)2). Regarding liquid propulsion, ADN-based formulations have already been employed in propulsive systems of satellites and proved to have performance advantages with respect to hydrazine. On the other hand, for solid propulsion, the challenge of finding a satisfactory composition, that could match the requirements to start an effective usage, is still opened. Several issues, such as incompatibility with isocyanates-based curing agents normally employed in the most common binders, high pressure exponent and high impact and friction sensitivities, affect ADN-based propellants. However, the potential performance advantage and absence of polluting combustion products that ADN would bring are worthy of the effort of studying it. Within this thesis project, the most significant results of recent research about this substance were assessed together with an analysis of innovative designs for future developments of Ariane family launchers. Moreover, three ADN-based solid formulations were analysed in order to assess their implementation into Ariane 5 solid boosters. The first two mixtures used glycidylazide polymer (GAP) as binder and a double-oxidizer configuration, with ADN/HMX in the former and ADN/ammonium nitrate in the latter. The third formulation contained a double-binder matrix of GAP and Desmophen D2200. Moreover, a further state-of-the-art composition based on the one of Ariane 5 boosters (EAP), was considered as a reference for comparisons. Analysis of the thermophysical properties, performance and chemical composition of the combustion products of each mixture was performed with the NASA CEA code. Considering the mission profile of the Ariane 5 boosters, the results obtained with CEA were then exploited to compute the most important features of solid rocket motors and the propulsive performances of each formulation. Moreover, a comparative evaluation, with respect to the AP-based formulation, of the presence of toxic and polluting substances in the combustion products was carried out.
L’industria spaziale e in particolare la propulsione sono state profondamente coinvolte dalla crescente consapevolezza sui valori dell’ecologia e dalla necessità di uno sviluppo eco-friendly. L’attuale stato dell’arte tecnologico per propellenti liquidi e solidi impiega formulazioni che generano prodotti tossici e pericolosi per l’ambiente. In particolare, le combinazioni liquide storabili per mono- e bi-propellenti si affidano principalmente all’ idrazina (N2H4) e ai suoi derivati, che hanno dato prova di essere cancerogeni. Riguardo alla propulsione solida, l’ossidante nelle formulazioni più comunemente utilizzate è il perclorato di ammonio (AP, NH4ClO4), che è tossico e la cui produzione porta alla contaminazione delle falde acquifere. Inoltre, la combustione di propellenti a base di AP genera grandi quantità di acido cloridrico (HCl), sostanza responsabile per le piogge acide e la riduzione dell’ozono atmosferico. Il perclorato di ammonio é attualmente utilizzato nella formulazione del propellente solido dei booster di Ariane 5. Nel prossimo futuro, è previsto che nuove normative Europee ridurranno o addirittura aboliranno l’utilizzo dell’AP. Queste considerazioni sottolineano chiaramente l’interesse nella ricerca di nuovi materiali per cosiddetti "green propellants". Una delle sostanze più promettenti per una possibile applicazione in propellenti green, sia liquidi che solidi, è la dinitroammina di ammonio (ADN, NH4N(NO2)2). Riguardo ai propellenti liquidi, formulazioni a base di ADN sono già state impiegate in sistemi propulsivi di satelliti e hanno mostrato vantaggi prestazionali rispetto all’idrazina. D’altro canto, per la propulsione solida, la sfida di trovare una composizione adeguata che possa soddisfare tutti i requisiti per iniziare un impiego effettivo, è ancora aperta. Diverse problematiche affliggono i propellenti a base di ADN, come l’incompatibilità con gli agenti curanti a base di isocianati normalmente impiegati con i binder più comuni, l’alto esponente di pressione e l’alta sensibilità agli impatti. Tuttavia, i vantaggi prestazionali e l’assenza di prodotti di combustione inquinanti che l’ADN apporterebbe rendono lo sforzo di studiarla degno di essere compiuto. In questo progetto di tesi, i risultati più significativi delle più recenti ricerche riguardanti questa sostanza sono stati valutati insieme agli sviluppi futuri della famiglia di lanciatori Ariane. Inoltre, tre formulazioni solide a base di ADN sono state analizzate per valutarne un’implementazione nei booster di Ariane 5. Le prime due miscele usano glycidylazide polymer (GAP) come binder e una configurazione a doppio ossidante con ADN/HMX nella prima e ADN/nitrato di ammonio nella seconda. La terza formulazione contiene una doppia matrice di binder con GAP e Desmophen 2200. Inoltre, è stata considerata un’ulteriore composizione stato dell’arte basata su quella dei booster (EAP) di Ariane 5 come riferimento per le comparazioni. Con il codice NASA CEA è stata condotta un’analisi delle proprietà termofisiche, delle performance e della composizione chimica dei prodotti di combustione di ogni miscela. Considerando il profilo di missione dei booster di Ariane 5, i risultati ottenuti con CEA sono stati sfruttati per calcolare gli aspetti più importanti dei motori a razzo solidi e le performance propulsive per ciascuna formulazione. Inoltre, è stata condotta una valutazione comparativa, rispetto alla formulazione a base di AP, della presenza di sostanze tossiche e inquinanti nei prodotti di combustione.
Analysis of ADN-based propellants for replacement of ammonium perchlorate in solid boosters
POZZONI, LUCA
2020/2021
Abstract
Space industry and particularly space propulsion are deeply affected by the growing awareness about the values of ecology and the needs of an environmental friendly technological development. Current state-of-the-art technologies for both liquid and solid propellants employ formulations that produce environmental hazardous and toxic products. In particular, liquid storable combinations for mono- and bi-propellants mainly rely on hydrazine (N2H4) or hydrazine-derived substances, which are proved to have carcinogenic implications. Regarding solid propulsion, the oxidizer in the most common formulations is ammonium perchlorate (AP, NH4ClO4), which is toxic and whose production leads to contamination of groundwater. Moreover, combustion of AP-based propellants produces great amounts of hydrogen chloride (HCl), a substance responsible for acid rains and ozone depletion. Ammonium perchlorate is currently employed in the propellant formulation of solid rocket boosters of the European launcher Ariane 5. In the near future, new European regulations are expected to reduce or even abolish the usage of AP. These considerations clearly highlight the interest in the investigation of materials for so called “green propellants”. One of the most promising substances for a possible application in both liquid and solid green propellants is ammonium dinitramide (ADN, NH4N(NO2)2). Regarding liquid propulsion, ADN-based formulations have already been employed in propulsive systems of satellites and proved to have performance advantages with respect to hydrazine. On the other hand, for solid propulsion, the challenge of finding a satisfactory composition, that could match the requirements to start an effective usage, is still opened. Several issues, such as incompatibility with isocyanates-based curing agents normally employed in the most common binders, high pressure exponent and high impact and friction sensitivities, affect ADN-based propellants. However, the potential performance advantage and absence of polluting combustion products that ADN would bring are worthy of the effort of studying it. Within this thesis project, the most significant results of recent research about this substance were assessed together with an analysis of innovative designs for future developments of Ariane family launchers. Moreover, three ADN-based solid formulations were analysed in order to assess their implementation into Ariane 5 solid boosters. The first two mixtures used glycidylazide polymer (GAP) as binder and a double-oxidizer configuration, with ADN/HMX in the former and ADN/ammonium nitrate in the latter. The third formulation contained a double-binder matrix of GAP and Desmophen D2200. Moreover, a further state-of-the-art composition based on the one of Ariane 5 boosters (EAP), was considered as a reference for comparisons. Analysis of the thermophysical properties, performance and chemical composition of the combustion products of each mixture was performed with the NASA CEA code. Considering the mission profile of the Ariane 5 boosters, the results obtained with CEA were then exploited to compute the most important features of solid rocket motors and the propulsive performances of each formulation. Moreover, a comparative evaluation, with respect to the AP-based formulation, of the presence of toxic and polluting substances in the combustion products was carried out.File | Dimensione | Formato | |
---|---|---|---|
Luca Pozzoni TESI CORRETTA.pdf
accessibile in internet solo dagli utenti autorizzati
Dimensione
8.81 MB
Formato
Adobe PDF
|
8.81 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/10589/174012