The Relation between Burning Time and Burning Energy of HTPB - Based Composite Propellant

This paper represented a result of several visions of chemical phenomenon and several extractions and extrapolations of experimental works which included a relationship between energy related to a chemical process and the relevant time which is required to achieve this process, but it must be taken into account that those mentioned experimental works hadn’t aimed substantially to study and state this relationship neither implicitly nor explicitly, but the results of those works have been exploited for another field after being compared with the relevant thermodynamic calculations. The selected case study for this paper was the relation between the burning time of Hydroxyl terminated poly butadiene propellant ( HTPB) and the caloric value of this material. The results reflected some relationship between the burning time and the change of the system energy during the burning process.

Challenges of Ablatively Cooled Hybrid Rockets for Satellites or Upper Stages

Ablative-cooled hybrid rockets could potentially combine a similar versatility of a liquid propulsion system with a much simplified architecture. These characteristics make this kind of propulsion attractive, among others, for applications such as satellites and upper stages. In this paper, the use of hybrid rockets for those situations is reviewed. It is shown that, for a competitive implementation, several challenges need to be addressed, which are not the general ones often discussed in the hybrid literature. In particular, the optimal thrust to burning time ratio, which is often relatively low in liquid engines, has a deep impact on the grain geometry, that, in turn, must comply some constrains. The regression rate sometime needs to be tailored in order to avoid unreasonable grain shapes, with the consequence that the dimensional trends start to follow some sort of counter-intuitive behavior. The length to diameter ratio of the hybrid combustion chamber imposes some packaging issues in order to compact the whole propulsion system. Finally, the heat soak-back during long off phases between multiple burns could compromise the integrity of the case and of the solid fuel. Therefore, if the advantages of hybrid propulsion are to be exploited, the aspects mentioned in this paper shall be carefully considered and properly faced.

Processing of Wild Sunflower with Different Moisture Contents into Solid Bio Fuel

Wild sunflower with moisture contents of 16%, 12% and 8% was densified without the addition of binding agent. The physical properties of the formed briquettes such as mass, dimensions, volume, density and shattering resistance were evaluated. Thermal properties like ignition time, burning time, ash content, and thermal fuel efficiency by means of boiling test were also evaluated. Wild Sunflower stems were gathered and shredded using locally fabricated biomass shredder available at the Research Office of Benguet State University, and were processed into the desired size and moisture contents. Right after the briquetting operation, the physical properties of the briquette were measured and then stored in a zip bag for 24 hours. After the storage, same measurement was conducted. Results show that the influence of moisture contents on the average mass, dimension, shattering resistance, volume and density was statistically insignificant. The wild sunflower with moisture content of 16% had the highest shattering resistance of 88.85%. Furthermore, the influence of moisture content on the thermal properties like ignition time, burning time and ash content are statistically insignificant. Among the moisture contents, the fastest ignition time of 43.75 sec with longest burning time was recorded under 12%. Ash content was also lowest at 12%.

Thermo-physiological properties and burning behaviours of automotive upholstery fabrics woven with aramid and wool yarns

Today, people’s expectations of cars have changed because they travel more frequently and take much longer trips in their automobiles. Therefore, auto manufacturers have come to realize that comfort properties of automobiles should be improved in addition to their mechanical, technical and aesthetical properties. This study aimed to investigate the thermophysiological properties of the automotive upholstery woven fabrics produced with different blend ratios of flame resistant meta-aramid and wool yarns. For this purpose, twenty-eight automotive upholstery woven fabric samples were produced using two different weaving patterns and different blend ratios of flame resistant meta-aramid and wool yarns. Thermophysiological properties of the samples such as water vapor permeabilities, air permeabilities and thermal conductivities were measured, and their burning behaviours were tested according to the standards. The results obtained in this study were assessed by means of statistical methods, and the results of the statistical analysis showed that blending ratios of flame resistant meta-aramid and wool fiber had statistically significant effects on both the thermo-physiological properties and burning behaviours of automotive upholstery fabrics. This study showed that the thermal comfort values of the automotive upholstery fabrics of different meta-aramid/wool blend ratios were very close to one another. In addition, the air permeability values of these fabrics were increased with the increase of the meta-aramid content in the blend. The blends containing 25% meta-aramid fiber exhibited the highest increases in air permeability values of the fabrics. Besides, the blend of 25% meta-aramid and 75% wool fiber was found to be the optimal blending ratio in terms of the total burning time after the removal of the ignition source. Therefore, it can be concluded that thermo-physiological comfort properties and burning behaviours of automotive upholstery fabrics can be improved by using the blends with different meta-aramid contents, depending on desired fire performance levels and thermophysical properties.

Preparation and Characterization of Bio-Adsorbent from Coconut Husk for Remazol Red Dye Removal

This study aimed to evaluate the effectiveness of bio-adsorbent from coconut husk for the removal of remazol red dye. The characteristics of coconut husk bio adsorbent are studied using Fourier transform infrared (FT-IR) and scanning electron microscope (SEM). The effects of different types of adsorbent and the effects of initial dye concentration on the removal of remazol red dyes were evaluated. The results showed that the percentage removal of remazol red dye by the treated bio adsorbent is higher compared to the untreated bio adsorbent, especially by activated coconut husk with 5 hours burning time in the furnace. The SEM results also show that the treated bio adsorbent morphology is more porous and rougher to improve the adsorption process. Meanwhile, FTIR analysis shows the reduction of peaks because of the removal of much lignin and hemicelluloses. The best adsorbent recorded is activated coconut husk at 5 hours burning time when it achieved 75% removal.

Aluminum Combustion under Different Condition: A Review

This paper reviews the collection of literature on aluminum combustion, with an emphasis on various parameters used. These parameters which affect combustion of aluminum are particles size and oxygen content. Aluminum is a material that is often used in combustion processes due to its effortless reactive material and explosive. A large amount of research has been published about combustion in aluminum materials where aluminum can be used as a way to increase propulsion in combustion. The purpose of this paper is to review some aspects that affect combustion in aluminum. It goes on to discuss the particles size differences and the different oxygen content mixture with gas in used. The results of various existing studies show that there is a difference in ignition temperature and burning time effect in aluminum combustion due to the size and oxygen content. Where, decreasing particles size can decrease ignition temperature and burning time. The review paper is intended to outline a parameter range for aluminum combustion.