The thesis introduces a methodology for designing and sizing a low-altitude small-scale prototype airship featuring ionic plasma thrusters. The methodology is based on an approach described by Carichner and Niocali , which employs an iterative process based on an initial guess of the length of the airship and it is predefined with mission requirements and assumptions such as the structure, material, aspect ratio, type of propulsion system employed, aerodynamics, etc. This leads to the determination of airship geometry and performance metrics. Regarding the ion thruster, it consists of wire emitters and 5 airfoils as collectors, the type of airfoil employed is NACA 0010 or any other symmetrical airfoil type is applicable as well. Moreover, to determine the size of the ion thruster and obtain its performance, the thrust density and thrust-to-power ratio are derived from experimental analysis by Belan et al. or from the recent experimental findings by the Aerospace Engineering Department at Politecnico di Milano (DAER). Using these values, the frontal area of the ion thruster, as well as the thrust and power outputs, are calculated. In addition, CAD software could be employed to calculate the total weight of the ion thruster including airfoils, structural support, and wire emitters. Instead of relying on CAD models, the weight of the ion motor can be determined by using the thrust-to-weight ratio, a value derived from experimental data provided by DAER. By superimposing the methodology for sizing the aircraft and ion thruster experimental analysis results, the weight breakdown and mission performance metrics of the airship are determined, as well as, the thruster performance parameters. Thereafter, an analysis of longitudinal static stability is performed to observe how the angle of attack (α) and deflection angle (δ) behave across different velocities, from 1 m/s to 10 m/s, and to identify the optimal center of gravity position through its range.
La tesi introduce una metodologia per la progettazione e il dimensionamento di un prototipo di dirigibile su piccola scala a bassa quota dotato di propulsori al plasma ionico. La metodologia si basa su un approccio descritto da Carichner e Niocali , che impiega un processo iterativo basato su un’ipotesi iniziale della lunghezza del dirigibile ed è predefinito con requisiti e ipotesi di missione come struttura, materiale, proporzioni, tipo di sistema di propulsione utilizzato, aerodinamica, ecc. Ciò porta alla determinazione della geometria del dirigibile e delle metriche delle prestazioni. Per quanto riguarda il propulsore ionico, è costituito da emettitori di filo e 5 profili alari come collettori, il tipo di profilo alare utilizzato è NACA 0010 o è applicabile anche qualsiasi altro tipo di profilo alare simmetrico. Inoltre, per determinare la dimensione del propulsore ionico e ottenerne le prestazioni, la densità di spinta e il rapporto spintapotenza sono derivati dall’analisi sperimentale di Belan et al o dai recenti risultati sperimentali del Dipartimento di Ingegneria Aerospaziale al Politecnico di Milano (DAER). Utilizzando questi valori, vengono calcolate l’area frontale del propulsore ionico, nonché la spinta e la potenza. Inoltre, il software CAD potrebbe essere utilizzato per calcolare il peso totale del propulsore ionico, compresi i profili alari, il supporto strutturale e gli emettitori di fili. Invece di fare affidamento su modelli CAD, il peso del motore ionico può essere determinato utilizzando il rapporto spinta-peso, un valore derivato dai dati sperimentali forniti da DAER. Sovrapponendo la metodologia per il dimensionamento dei risultati dell’analisi sperimentale dell’aereo e del propulsore ionico, vengono determinati la ripartizione del peso e i parametri delle prestazioni della missione del dirigibile, nonché i parametri delle prestazioni del propulsore. Successivamente, viene eseguita un’analisi della stabilità statica longitudinale per osservare come l’angolo di attacco (α) e l’angolo di deflessione (δ) si comportano a diverse velocità, da 1 m/s a 10 m/s, e per identificare la posizione ottimale del baricentro attraverso il suo intervallo.
Preliminary sizing, mass lofting, and trimming of a small-scale airship featuring ion-plasma propulsion
Shehata, Anas Masoud Saad Mahmoud
2022/2023
Abstract
The thesis introduces a methodology for designing and sizing a low-altitude small-scale prototype airship featuring ionic plasma thrusters. The methodology is based on an approach described by Carichner and Niocali , which employs an iterative process based on an initial guess of the length of the airship and it is predefined with mission requirements and assumptions such as the structure, material, aspect ratio, type of propulsion system employed, aerodynamics, etc. This leads to the determination of airship geometry and performance metrics. Regarding the ion thruster, it consists of wire emitters and 5 airfoils as collectors, the type of airfoil employed is NACA 0010 or any other symmetrical airfoil type is applicable as well. Moreover, to determine the size of the ion thruster and obtain its performance, the thrust density and thrust-to-power ratio are derived from experimental analysis by Belan et al. or from the recent experimental findings by the Aerospace Engineering Department at Politecnico di Milano (DAER). Using these values, the frontal area of the ion thruster, as well as the thrust and power outputs, are calculated. In addition, CAD software could be employed to calculate the total weight of the ion thruster including airfoils, structural support, and wire emitters. Instead of relying on CAD models, the weight of the ion motor can be determined by using the thrust-to-weight ratio, a value derived from experimental data provided by DAER. By superimposing the methodology for sizing the aircraft and ion thruster experimental analysis results, the weight breakdown and mission performance metrics of the airship are determined, as well as, the thruster performance parameters. Thereafter, an analysis of longitudinal static stability is performed to observe how the angle of attack (α) and deflection angle (δ) behave across different velocities, from 1 m/s to 10 m/s, and to identify the optimal center of gravity position through its range.| File | Dimensione | Formato | |
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https://hdl.handle.net/10589/219742