Nitrogen Propellant Research Articles

Computational and experimental research on the performance of ECRIT ion source with nitrogen propellant

Electron cyclotron resonance ion thruster (ECRIT) with a diameter of 2 cm has the characteristics of no hot cathode and high specific impulse, which is suitable for the air-breathing electric propulsion system. In order to adapt to the atmospheric composition characteristics of nitrogen and oxygen in low orbit, the computational and experimental research on the performance of the ECRIT ion sourse with nitrogen propellant is an important basis for analyzing the feasibility of applying ECRIT to the air-breathing electric propulsion system. In this paper, the global model of the nitrogen ECRIT ion source with a diameter of 2 cm is established to calculate its performance. Then, the computational results are compared with the experimental results to analyze the difference. The research results show that when the input power of the ion source is 8 W and the gas flow rate is 2 ml/min, the computational and experimental results of the extracted ion beam current and thrust reach the maximum with the extracted beam current of 16.2 and 12.5 mA and the thrust of 476.6 and 368 μN, respectively. When the input power is 8 W and the gas flow rate is 0.6 ml/min, the computational and experimental results of the specific impulse are 2 095.8 and 1 855.6 s, both reaching the maximum value. The relative errors between the computational and experimental results of the extracted ion beam current, thrust and specific impulse all range from 2% to 32%. When the input power and gas flow rate used are 8 W and 1 ml/min in calculation, and 8 W and 0.8 ml/min in experiment, the ion source is on the optimal operating state. At this situation, the computational and experimental propellant utilization efficiencies with 17.8% and 16.2% respectively are high, and the ion energy loss with 443.9 and 596.2 W/A respectively is low.

Effect of He and N2 gas on the mechanical and tribological assessment of SS316L coating deposited by cold spraying process

In this study, simulation and experimental methods were used to investigate the influence of cold spray conditions on AISI 316L stainless steel coatings. The effect of both helium and nitrogen gases used was investigated. The temperature, particle sizes of spraying powder, and distance from the nozzle throat to the impinging point were estimated by using the Kinetics Spray Solutions GmbH software. The 316L stainless steel (SS) coatings were examined by X-ray diffraction, Scanning Electron Microscopy and Energy Dispersive X-Ray Microanalysis. The tribological behavior was evaluated under different loads (2 N and 5 N) in dry conditions. It was found that the nitrogen and helium propellant gas with high speed and fine particles led to produce good coatings with dense microstructures. From the nanoindentation experiments, the Young's modulus and hardness of the SS 316L samples were enhanced of about 8% with helium due to the high particle velocity. It was shown that the wear resistance of SS 316L produced with helium was higher than that of the standard SS 316L coatings. The coatings produced with helium revealed lower friction coefficient (0.65) and wear rate (6.9 × 10–4 mm3/Nm) under 2 N applied load than that obtained nitrogen. It was also found that the SS 316L cold sprayed by helium with dense structure presents high hardness and good tribological performance that can be suggested for several applications.Graphical

Dual mode operation of a hydromagnetic plasma thruster to achieve tunable thrust and specific impulse

We report here on initial studies of a pulsed hydromagnetic plasma gun that can operate in either a pre-filled or a gas-puff mode on demand. These modes enable agile and responsive performance through tunable thrust and specific impulse. Operation with a molecular nitrogen propellant is demonstrated to show that the hydromagnetic thruster is a candidate technology for air-harvesting and drag compensation in the very low Earth orbit. A dual mode operation is achieved by leveraging propellant gasdynamics to change the fill fraction and flow collisionality within the thruster. This results in the formation of distinct modes that are characterized by the current-driven hydromagnetic waves that they allow, namely, magneto-deflagration and magneto-detonation, respectively. These modes form the basis of using gasdynamics to enable responsive thruster performance. Using time-of-flight emission diagnostics to characterize near-field flow velocities, we find that a relatively dramatic transition occurs between modes as gas is allowed to expand in the thruster, with exhaust velocities ranging from 10 to 55 km/s in the deflagration and detonation regimes, respectively. Simulations of the processed mass bit offer the first glimpse into possible thruster performance and trade-offs between specific impulse and thrust. An impulse bit tunability of ∼22% is predicted, with differing propellant fill fractions when operating in a burst mode.

Thermal Design and Experimental Verification of a Three-Dimensional-Printed Resistojet

A high-efficiency concentric tubular-type resistojet with potential application to short-term orbit-raising maneuvers has been fabricated by 3-D printing and demonstrated. The propellant flows through multiple layers of cylindrical shells, with this structure also functioning as a single-piece heater. A 6-cm-high cylinder was realized with a wall thickness of 0.2 mm, using Inconel 718. A nodal thermal analysis was performed to identify the upper-limit current at a temperature limit of the wall material, and it was revealed that an outlet gas temperature of 871 K can be achieved with 77 A of current at 0.2 g/s of mass flow rate. The designed heater was combined with a boron nitride insulator and a stainless-steel housing, and thrust was measured in a vacuum chamber with nitrogen as the propellant. At a mass flow rate of and 75 A of current, an outlet temperature of 747 K, a specific impulse of 108 s, and a heater efficiency of 72% were achieved. These results with nitrogen propellant were used to predict the performance of a tungsten-made resistojet with a hydrogen propellant, and a specific impulse of over 700 s can be expected at a heater temperature of 2000 K.

Extended channel Hall thruster for air-breathing electric propulsion

Air-breathing electric propulsion is a promising concept that may allow sustained access to very low earth orbit by guaranteeing continuous drag compensation through in situ harvesting of propellant. For earth observation, such low orbits benefit image resolution and reduce signal latency and transmission power requirements, easing link budgets. Moreover, not having to carry typical electrostatic thruster propellants such as xenon and tanks positively impact overall mission costs. However, the low molecular mass and high first ionization energies of principal atmospheric constituents hinder efficient thruster operation and result in strongly degraded performance. In this study, we examine the performance of an extended channel Hall thruster design for air-breathing operations. An extended channel compensates for the reduced residence times of lighter neutrals. The longer channel, coupled with an extended radial magnetic field region, allows for an increased length of the ionization zone, enhancing molecular ionization probability. Here, we present direct thrust measurements of this thruster operating with a pure nitrogen flow. Analysis of the results show performance in the 500–800 W anode power range, with thrust, specific impulse, and total thrust efficiency ranging from 17 to 22 mN, 1000 to 1100 s, and 14% to 18%, respectively, with a constant 2 mg/s pure molecular nitrogen propellant flow. Performance tends to degrade with increased voltage, suggesting increased contributions of electron-molecule kinetics to performance losses, contrary to what is typically seen in the Hall thrusters operating with propellants such as xenon.

Bimodal Propulsion System for Small Spacecraft: Design, Fabrication, and Performance Characterization

The use of multimodal space propulsion has the benefit of increasing satellite mission flexibility with the ultimate goal of decreasing mission development costs. The present paper explores the development of a dual-mode thruster for small spacecraft. By combining an electrospray within the confines of a cold gas nozzle, the fabricated and tested propulsive device can operate either in a high thrust or high specific impulse mode. The thruster herein makes use of a laser microfabricated porous glass triangular prism electrospray emitter using passively fed ionic liquid () as propellant. The electrospray performance has been indirectly quantified with beam current measurements on the order of at an extraction voltage of 2.5 kV, which correlates to a significantly lower thrust than expected. For the second thrust mode, cold gas thrust and specific impulse were measured directly to be 7.9 mN and 44 s, respectively, using nitrogen propellant. The operation of this device in both modes has exemplified its potential applicability to microspacecraft while demonstrating the tradeoffs of bimodal thruster design.

Effect of Cold-Spray Conditions Using a Nitrogen Propellant Gas on AISI 316L Stainless Steel-Coating Microstructures

Cold-spray techniques have been a significant development for depositing metal coatings in recent years. In cold-spray processes, inexpensive nitrogen gas is widely used as the propellant gas in many industries. However, it is difficult to produce austenitic stainless steel coatings with dense microstructures with cold-spray techniques when using nitrogen propellant gas because of work hardening. In this study, the effects of cold-spray conditions using a nitrogen propellant gas on AISI 316L stainless steel coatings were examined. It was found that a higher nitrogen propellant gas temperature and pressure produce coatings with dense microstructures. The measured AISI 316L coating hardness values suggest that AISI 316L particles sprayed at temperatures of 700 and 800 °C soften due to the heat, allowing uniform deformation on the substrate and consequently forming dense coating microstructures. In addition, AISI 316L powder with particle diameters of 5–20 µm resulted in a denser coating microstructure than powder with particle diameters of 10–45 and 20–53 µm. Finally, the standoff distance between the nozzle and the substrate also affected the AISI 316L coating microstructures; a standoff distance of 40 mm produced the densest microstructure.

Micro-multi-plasmajet array thruster for space propulsion applications

In this study, the characteristics of a 6 × 6 micro-multi-plasmajet array thruster were examined in vacuum. The discharge and thrust characteristics were examined experimentally. For the discharge operation, a stable and uniform plume from each nozzle element across an arrayed nozzle was observed at total nitrogen propellant mass flow rates ranging from 2.1 to 37.5 mg/s and total discharge currents ranging from 20 to 40 mA. Typical values of thrust, specific impulse, and thrust efficiency at a mass flow rate of 37.5 mg/s and an input power of 27 W were 39 mN, 107 s, and 0.33, respectively. Moreover, thrust performance of the 6 × 6 micro-multi-plasmajet array thruster was compared with a conventional 3 × 3 micro-multi-plasmajet array and micro single plasmajet thrusters. It was shown that the average thrusts per nozzle element of the 3 × 3 and 6 × 6 micro-multi-plasmajet array thrusters were two and three times higher, respectively, than the micro-single plasmajet thruster.

Low pressure cold spraying under 6 bar pressure deposition: Exploration of high deposition efficiency solutions using a mathematical modelling

Abstract This paper investigates the improvement of the deposition efficiency (DE) for low pressure cold spraying. In the literature, some possibilities were studied (a long preheating of the powder feedstock, the use of irregular shaped particles, the combination of metallic particle with ceramics, or the laser assisted heating) but the DE is still weak, in the range of 10%, when working at around 6 bar. In this paper, the improvement possibilities depending on the gas conditions, the particle size and the nozzle geometry are explored. The deposition of spherical copper powder onto a copper substrate is considered. Experimental investigations evidence a low DE of about 0.1 and virtual tests computing the one-dimensional flow of the gas through the nozzle and the interaction with the particles are used to identify potential solutions increasing the DE. Air or nitrogen propellant gas has led to similar DE. The highest achieved value remains low even working at the maximum capacity of the low pressure system, i.e. a gas with an inlet pressure of 12 bar and a preheating temperature of 630 °C. Factors of improvement are suggested for the specific case of the standard pressure of 6 bar. Fine particles cause clogging and larger particles are difficult to be efficiently deposited. Successful combinations promoting the DE include a nozzle expansion ratio in between 1.2 and 2, a diverging part length in between 200 mm and 300 mm and the helium propellant gas preheated at 600 °C. Hence the DE can reach up to 100% for 10 μm sized copper particles according to the computation. If using larger particles (20 μm, 30 μm or 40 μm), the maximum DE is respectively 0.7, 0.5 or 0.3 approximately. This results give indications for the suitable conditions promoting the highest achievable DE for low pressure cold spraying.

OS9-13 Performance Evaluation of Single Stage Diaphragmless Vertical Gas Gun for Nitrogen and Helium Gas Propellants(Shock and Hypervelocity Impact,OS9 Recent advances in impact engineering,STRENGTH OF MATERIALS)

OS9-13 Performance Evaluation of Single Stage Diaphragmless Vertical Gas Gun for Nitrogen and Helium Gas Propellants(Shock and Hypervelocity Impact,OS9 Recent advances in impact engineering,STRENGTH OF MATERIALS)

Effect of Heat Treatment on the Microstructure and Mechanical Properties of Stainless Steel 316L Coatings Produced by Cold Spray for Biomedical Applications

Abstract In this study, the effects of heat treatment on the microstructure and mechanical properties of cold sprayed stainless steel 316L coatings using N2 and He as propellant gases were investigated. Powder and coating characterizations, including coating microhardness, coating porosity, and XRD phase analysis were performed. It was found that heat treatment reduced porosity, improved inter-particle bonding, and increased ductility. XRD results confirmed that no phase transformation occurred during deposition. Significant increase in UTS and ductility was observed for the annealed specimens obtained with nitrogen propellant, whereas little changes were observed for the helium propellant produced specimen.

ジメチルエーテルを用いたアークジェット推進機の推力評価

The present paper describes performance evaluation of a Dimethyl Ether (DME) propellant arcjet thruster. We have proposed to apply DME to arcjet thrusters owing to its favorable characteristics for space propulsion device such as non toxicity, weak chemical reactivity and storability. Thrust measurement using a vertical-pendulum-type thrust stand showed that thrust was almost monotonously increased with mass flow rate at a given discharge current, and rose with specific power. Specific impulse was also enhanced with specific power whereas thruster efficiency was attenuated. DME propellant presented higher thrust, specific power and thruster efficiency than nitrogen propellant at a given discharge current or specific power. Thrust measurement yielded a thrust of 0.19N, a specific impulse of 330s, thruster efficiency of 0.14 at a DME flow rate of 60-mg/s with the corresponding discharge voltage, power, and specific power of 90V, 2350W, and 39MJ/kg, respectively.

Demonstration of Microcoil Heaters for Microthrusters

The resilience and performance of carbon microcoil heaters made by laser-induced chemical vapor deposition (LCVD) to be used as an efficient means for increasing the specific impulse of cold/hot gas microthrusters were investigated. Two naked carbon coils and two tungsten coated carbon coils coated through LCVD were used in this experiment. Each pair of coated and uncoated carbon coils were heated resistively in a thermal cycling between 300-1173K and 973-1173K for 2 h in 0.000003 mbar and 2 bar N. The results show that at these temperatures the carbon microcoils and nitrogen propellant were compatible while the tungsten coated microcoils started degrading. It was observed that LVCD-deposited carbon and tungsten-coated carbon microcoils can withstand low to medium-high temperatures for extended periods of time during thermal cycling without showing signs of degradation.

Numerical Analysis of Free-Molecule Microresistojet Performance

The direct-simulation Monte Carlo method was used to study the flow in a free-molecule microresistojet (FMMR). The FMMR is a microelectromechanical-systems (MEMS) fabricated resistojet that operates by heating a propellant gas as it expands through a series of slots. The flow through a single heater slot of the FMMR was modeled in two dimensions for a range of chamber pressures from 50 to 200 Pa and heater chip temperatures from 300 to 573 K. Using this, the numerical performance of FMMR was computed. The resultant specific impulse was found to agree within 2% of experimental data for nitrogen propellant and within 4% for helium propellant. Then, a full three-dimensional model of the FMMR geometry was made for water vapor as propellant in two steps. First, the flow in the plenum was modeled. FMMR performance parameters were found to be 10% lower than those of the two-dimensional model. Second, the FMMR plume flow was calculated using a starting surface generated from the plenum simulation for two possible locations of the FMMR as a despin thruster on a nanosatellite. The thrust degradation caused by the resultant surface forces was examined, and the net moment of one configuration was found to be 60% higher than the other.

Facial burns after exposure to CS spray

2-Chlorobenzylidene malononitrile (CS) was developed in 1928 by Corson and Stoughton. It replaced chloroacetophenone (CN) as riot control agent and self-defence spray in the late 1950s due to its increased potency but more importantly, less toxicity. It is the most widely used form of 'tear gas'. The British Police force have used it since its introduction in March 1996 and use a 'spray' containing 5% CS (w/v) in a solvent of methylisobutylketone (MIBK) with a nitrogen propellant. Advocates of its use claim, that if used correctly, the noxious effects are transient, and mainly manifest as lacrimation and irritation respiratory tract. Generally CS sprays appear to be safe if used in a controlled manner. We present a case of facial and upper body chemical burns resulting from the use of CS spray in the UK. The police restrained a 24-year-old man after a domestic disturbance in the early hours of the morning. CS was sprayed onto the face and upper body and then the man was handcuffed. After release from police custody, he presented himself to his local Accident and Emergency Department the following evening complaining of burns to his face and upper body as well as pain in the shoulders and wrists related to his arrest. CS is a white solid with a low vapour pressure that is released as an aerosol of fine particles or in solution. The microscopic particles act as potent sensory irritants, especially on moist skin and mucous membranes. It is an alkylating agent and reacts at nucleophilic sites. Although unclear, injuries related to this class of agents may be caused by the inactivation sulphhydryl-containing enzymes such as lactate dehydrogenase and coenzymes in the pyruvate decarboxylase system.4 Onset of symptoms usually occurs in the first minute after exposure with severe pain in the eyes and sensitive areas of the face. This is followed by lacrimation, visual disturbance, blephorospasm, rhinorrhoea, sneezing, coughing, retching, tightness in the chest and a burning sensation in the nose, throat and exposed skin. The severity of reaction depends upon the duration of exposure, concentration of the CS, moistness of the skin and whether the patient is in a restricted environment. The effects are usually temporary (reduced if in an 'open' environment) resolving in 30 min. Severe burns related to CS exposure have been attributed to flame burns from the explosion of gas-grenades, contact burns when hot canisters touched victims' bodies, burns related to the MIBK solvent which in itself is an ocular and skin irritant, and delayed cutaneous hypersensitivity reactions related to previous exposure.3 In this case report, the most likely cause is a combination of the CS and MIBK resulting in a chemical burn. The confined environment and perspiration associated with the domestic dispute sought to aggravate the physiological response. Following exposure to CS patients should be well aerated, and contaminated clothes removed. In the UK, blowing dry air from a hair dryer to force evaporation is the preferred method for facial exposure,5 while irrigation with normal saline to the rest of the body can be used.1 CS is known to have other serious toxic side effects such as miscarriage, hepatitis, pneumonitis and reactive airway dysfunction syndrome (recurrent cough and wheezing).2 Use of CS in a confined space is not advised due to the increased risk of severe toxic reaction.

Novel High Nitrogen Propellant Use in Solid Fuel Micropropulsion

The use of two novel materials, 3,6-bis(1H-1,2,3,4-tetrazol-5-ylamino)-s-tetrazine (BTATz) and mixed N-oxides of 3,3'-azo-bis(6-amino-1,2,4,5-tetrazine) (DAATO3.5, where the 3.5 indicates the average oxide content), as solid fuels in micropropulsion systems is investigated. These materials were selected due to their ease of ignition, relatively good safety characteristics, long-term storage capability, low combustion temperature, noncorrosive combustion products, and reasonable projected material cost. Material safety data including impact, friction, differential scanning calorimetry, and electrostatic sensitivity are reported and compared to the previously implemented micropropulsion fuels, lead styphnate, glycidyl azide polymer (GAP) and 3,6-diamino-1,2,4,5-tetrazine-1,4-dioxide. Burn rate data are also reported for both materials. Whereas BTATz and DAATO3.5 have very high burn rates, DAATO3.5 is believed to have the highest burn rate of any known stable organic solid. Additionally, DAATO3.5 has a very desirable pressure exponent of 0.28. Test stand results using a quartz microthruster are reported for these materials. Estimated chamber pressures reached 18 atm with peak thrust levels around 0.1 N. Measured specific impulses of approximately 14% of the theoretical specific impulse (218 s for BTATz and 228 s for DAATO3.5) were obtained. This level of inefficiency is believed to be acceptable for micropropulsion systems and is comparable to other, independent work.

Gas dynamic calibration of a nano-Newton thrust stand

The ability to measure extremely low thrust levels with unusual precision is becoming more critical as attempts are made to characterize the performance of emerging micropropulsion systems. Many new attitude control concepts for nanospacecraft involve the production of thrust below 1 μN. A simple, but uniquely successful thrust stand has been developed and used to measure thrust levels as low as 86.2 nano-Newtons (nN) with an estimated accuracy of ±11%. Thrust levels in the range of 712 (nN) to 1 μN have been measured with an estimated accuracy of ±2%. Thrust is measured from an underexpanded orifice operating in the free molecule flow regime with helium, argon, and nitrogen propellants. The thrust stand is calibrated using results from direct simulation Monte Carlo numerical models and analytical solutions for free molecule orifice flow. The accuracy of the gas dynamic calibration technique, using free molecule orifice flow, has also been investigated. It is shown that thrust stand calibration using high Knudsen number helium flow can be accurate to within a few percent in the 80 to 1 μN thrust range for thin walled orifices when the stagnation pressure is accurately measured. The thrust stand and calibration technique exhibit significant improvement for accurate, low thrust measurements compared to currently published results.

Dynamic voltage-current characteristics of a megawatt MPD-ARC thruster

The dynamic voltage-current characteristic of a hot cathode, megawatt (Mw), pulsed MPDARC thruster are given for various axial magnetic fields (1.0-2.0 T). The arc is powered by a crowbarred capacitor bank, and the transient data is obtained for the 100 /zsec period after crowbar time. Each shot shows a positive sloped characteristic. A series of these dynamic characteristics, spanning 2—14 ka, along with estimated static characteristics are given for argon and for nitrogen propellant. As the magnetic field increases, the dynamic curves tend to be more identifiable as part of a connected, positive sloped line.