Preliminary results of the particle packing density theory for improving the theoretical density of composite propellant

2021 ◽  
Author(s):  
Bayu Prianto ◽  
Henny Setyaningsih ◽  
Anita Pinalia
Keyword(s):  
Packing Density ◽  
Particle Packing ◽  
Theoretical Density ◽  
Composite Propellant ◽  
Preliminary Results

The influence of particle packing density on wood combustion in a fixed bed under oxy-fuel conditions

Energy ◽  
2020 ◽  
Vol 194 ◽  
pp. 116863
Author(s):  
J.K. Tanui ◽  
P.N. Kioni ◽  
T. Mirre ◽  
M. Nowitzki ◽  
N.W. Karuri
Keyword(s):  
Packing Density ◽  
Fixed Bed ◽  
Particle Packing ◽  
Wood Combustion

scholarly journals Determination of the optimal replacement content of Portland cement by stone powder using particle packing methods and analysis of the influence of the excess water on the consistency of pastes

2019 ◽  
Vol 12 (2) ◽  
pp. 210-232 ◽  
Author(s):  
H. F. CAMPOS ◽  
T. M. S. ROCHA ◽  
G. C. REUS ◽  
N. S. KLEIN ◽  
J. MARQUES FILHO
Keyword(s):  
Portland Cement ◽  
Silica Fume ◽  
Packing Density ◽  
Particle Packing ◽  
Attractive Alternative ◽  
Excess Water ◽  
Stone Dust ◽  
Powder Content ◽  
Substitution Content

Abstract Cement is considered the basic component with the highest environmental impact in construction, in terms of CO2 emissions. As for the aggregates, the process of comminution of rocks, in addition to artificial sand, generates stone powder that ends up being stored outdoors, generating environmental damages. Thus, the replacement of cement by stone powder appears as an attractive alternative towards the sustainable concretes. In this context, the objective of this paper is to determine the maximum packing density in Portland cement, silica fume and stone dust pastes, to determine the optimal cement substitution content for the stone powder. In addition, it is intended to verify the influence of excess water on the consistency of the mixtures produced. The substitution was done in contents equal to 0%, 7%, 14% and 21% by volume and, for each content, the packing density was determined analytically by CPM model and combinations were reproduced experimentally. Excess water was checked by the mini Kantro cone test. The results showed that the higher cement substitution content of the stone powder obtained the higher packing density, experimental and analytical, and the higher workability, allowing economic and environmental advantages. Analyzing each material, the stone powder resulted in the highest packing density and silica fume is the lowest one. Therefore, finer particles resulted in lower packaging densities, due to the greater specific surface area, which demands more water. The agglomeration resulted in more empty gaps between the grains. In addition, mixtures flowability increased with the increase of the stone powder content. As the excess water is responsible for mixture lubrication, a higher packing density for a given volume of water improves the flowability.

scholarly journals Thixotropic Behavior in Defining Particle Packing Density of Highly Filled AP/HTPB-Based Propellant

Symmetry ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1767
Author(s):  
Afni Restasari ◽  
Luthfia Hajar Abdillah ◽  
Retno Ardianingsih ◽  
Hamonangan Rekso Diputro Sitompul ◽  
Rika Suwana Budi ◽  
...  
Keyword(s):  
Packing Density ◽  
Relative Viscosity ◽  
Particle Packing ◽  
Peak Time ◽  
Curing Process ◽  
Stress Growth ◽  
Composite Solid Propellant ◽  
Thixotropic Behavior ◽  
Maximum Particle ◽  
Composite Solid

An alarming, asymmetric flame in rocket combustion originates from a composite solid propellant (CSP) containing defects. The defects are the result of a composition that exceeds the maximum particle packing density. Based on the structure analysis of CSP, the addition of plasticizer causes the correlation between the viscosity of CSP slurry and particle packing density to become uncertain. This work aims to investigate the influence of thixotropic behavior on the maximum particle packing density of CSP. A CSP with different thixotropic behavior was successfully produced using aluminum/plasticizer dioctyl adipate (DOA) of 12–24. During the curing process, viscosity and stress–growth were investigated. The structure of the CSP was defined using X-ray radiography. It is remarkably observed that the peak of thixotropy occurred at the 15th minute of the curing process. The particle packing density of CSP can be decisive for the relative viscosity at the peak time of thixotropic behavior. The CSP with the highest relative viscosity at the peak time was revealed to have voids in the upper part of the CSP. Thus, this parameter was proven to change the preceding parameter, viscosity that was measured at the end of mixing. Based on the stress–growth analysis, it is conceivable that the mechanism involves the time-dependent diffusion of DOA in weakening aluminum agglomerates.

Strength and Durability Evaluation by DEM Approach of Green Concrete Based on Gap-Graded Cement Blending

2012 ◽  
Vol 450-451 ◽  
pp. 631-640 ◽  
Author(s):  
L.B Nghi Le ◽  
Piet Stroeven
Keyword(s):  
Portland Cement ◽  
Packing Density ◽  
High Performance ◽  
Cementitious Materials ◽  
Particle Packing ◽  
Mineral Admixture ◽  
Discrete Element Modeling ◽  
Pore Characteristics ◽  
Positive Effects ◽  
Concurrent Algorithm

This paper discusses the particle packing background of cementitious materials. On micro-level the Portland cement and eventually the mineral admixture grains can be considered packed in the watery environment. Particularly for (super) high performance materials, the packing density can be quite significant. An economic and due to fast computer developments reliable way to study packing of the binder, is by modern discrete element modeling (DEM) approach. In this paper use is made of a concurrent algorithm-based dynamic system, HADES. Hydration is simulated based on spherical grains. Thereupon strength can be studied on the basis of packing density. For durability issues, the complex and tortuous 3D pore structure has to be investigated. This paper uses for the assessment of pore characteristics the robotics-inspired DraMuTS system. Hydrated Portland cement is compared with gap-graded rice husk ash-(RHA)-blended (green) Portland cement. Experiments on gap-graded RHA-blended PC concrete are used as reference. Packing density is shown improved by gap-graded packing. What is more spectacular are the effects of gap-grading with RHA on the pore characteristics obtained on the DEM-produced virtual materials. This paper discusses the expected positive effects on transport-based durability issues due to gap-graded packing-induced changes in the pore system

scholarly journals Analysis of Cohesive Microsized Particle Packing Structure Using History-Dependent Contact Models

2015 ◽  
Vol 138 (4) ◽  
Author(s):  
Raihan Tayeb ◽  
Xin Dou ◽  
Yijin Mao ◽  
Yuwen Zhang
Keyword(s):  
Particle Size ◽  
Coordination Number ◽  
Gaussian Distribution ◽  
Packing Density ◽  
Mean Value ◽  
Distribution Functions ◽  
Particle Packing ◽  
Size Distributions ◽  
Packing Structure ◽  
Contact Models

Granular packing structures of cohesive microsized particles with different sizes and size distributions, including monosized, uniform, and Gaussian distribution, are investigated by using two different history dependent contact models with discrete element method (DEM). The simulation is carried out in the framework of liggghts, which is a DEM simulation package extended based on branch of granular package of widely used open-source code LAMMPS. Contact force caused by translation and rotation, frictional and damping forces due to collision with other particles or container boundaries, cohesive force, van der Waals force, and gravity is considered. The radial distribution functions (RDFs), force distributions, porosities, and coordination numbers under cohesive and noncohesive conditions are reported. The results indicate that particle size and size distributions have great influences on the packing density for particle packing under cohesive effect: particles with Gaussian distribution have the lowest packing density, followed by the particles with uniform distribution; the particles with monosized distribution have the highest packing density. It is also found that cohesive effect to the system does not significantly affect the coordination number that mainly depends on the particle size and size distribution. Although the magnitude of net force distribution is different, the results for porosity, coordination number, and mean value of magnitude of net force do not vary significantly between the two contact models.

scholarly journals Predicting the soil moisture retention curve, from soil particle size distribution and bulk density data using a packing density scaling factor

2014 ◽  
Vol 18 (10) ◽  
pp. 4053-4063 ◽  
Author(s):  
F. Meskini-Vishkaee ◽  
M. H. Mohammadi ◽  
M. Vanclooster
Keyword(s):  
Particle Size ◽  
Soil Moisture ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Packing Density ◽  
Characteristic Curve ◽  
Scaling Factor ◽  
Particle Packing ◽  
Soil Particle ◽  
Physically Based

Abstract. A substantial number of models predicting the soil moisture characteristic curve (SMC) from particle size distribution (PSD) data underestimate the dry range of the SMC especially in soils with high clay and organic matter contents. In this study, we applied a continuous form of the PSD model to predict the SMC, and subsequently we developed a physically based scaling approach to reduce the model's bias at the dry range of the SMC. The soil particle packing density was considered as a metric of soil structure and used to define a soil particle packing scaling factor. This factor was subsequently integrated in the conceptual SMC prediction model. The model was tested on 82 soils, selected from the UNSODA database. The results show that the scaling approach properly estimates the SMC for all soil samples. In comparison to the original conceptual SMC model without scaling, the scaling approach improves the model estimations on average by 30%. Improvements were particularly significant for the fine- and medium-textured soils. Since the scaling approach is parsimonious and does not rely on additional empirical parameters, we conclude that this approach may be used for estimating SMC at the larger field scale from basic soil data.

Concrete Mix Design Using Particle Packing Method: Literature Review, Analysis, and Computation

2021 ◽  
Vol 2 (1) ◽  
pp. 83-102
Author(s):  
Shreya Sunil Tolmatti ◽  
◽  
Sanskruti Jaywant Jadhav ◽  
Sakshi Satish Jadhav ◽  
Mayur M. Maske ◽  
...  
Keyword(s):  
Packing Density ◽  
Particle Packing ◽  
Fine Aggregate ◽  
Density Method ◽  
Correlation Curve ◽  
Concrete Mix Design ◽  
Concrete Mix ◽  
Concrete Quality ◽  
Paste Content

Particle packing technology is used to reduce the amount of cement in concrete by optimizing the concrete mix, resulting in more sustainable concrete. In this study, four different methods were used to determine the distribution of the mixture presented; packing density method, packing density method, IS code method, and packing density method. In the packing density method, the paste content that exceeds the voids will increase along with the increase in the quality of the concrete. In cases of packing density, the cement-water ratio decreases with the quality of the concrete. In the packing of too many trials, trials and tribulations should be carried out to achieve the ratio of water-cement and paste content for a certain grade of concrete. This correlation curve helps reduce the experiments involved in determining the ratio of semen and paste content for a given concrete quality. The water and cement contents for the packing density and the IS code method are almost the same for each particular concrete class. The workability of concrete achieved was more in the packing density method than the IS code method for the same concrete quality, because the water-cement ratio was slightly higher in the packing density method than the IS code method. The required fine aggregate particles are more in terms of packing density method compared to the IS code method. Therefore, more water and cement are required in terms of packing density. The correlation curve can be used to determine the ratio of water-cement and paste the content that exceeds the voids for a certain concrete quality

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