Horizontal Silo Research Articles

Use of the CFD Tool to Analyze the Aeration Comportment in a Horizontal Silo

Storage in vertical and horizontal silos is commonly used worldwide, and its better understanding is essential to acquire and maintain product quality of the stored products.Environmental temperature inside the silos is the main factor that drives mass loss, grain biological activity, pest development and product respiration. Thus, the study of temperature behavior at several layers of the product throughout time is necessary to diminish loss and achieve higher storage time with minimum quality loss, profit, and yield. Aeration is a formidable tool that allow the maintenance of temperature and consequently becomes an important preventive method to avoid the problems stated before. Direct measurement of temperature in all directions inside the silo requires numerous expensive equipment and labor force and requires a large amount of time to provide valuable and trusty data. For these reasons, CFD (computational fluid dynamics) was utilized to solve this problem. CFX software satisfactory demonstrated velocity behavior within the horizontal silo containing wheat; however, the aeration ducts configuration did not offered support to the correct silo aeration.

Analysis of horizontal silo pressure distribution by filling method based on experimental data

The work presents an analysis of the results of the fill-in condition influence of particle inclination on horizontal silage pressure. Analyzed data were obtained from experiments on a rectangular silo model with rigid walls in a different fill-in condition. The filler was a composite mixture of sand and flat shell particles (2:1). The analysis of the results concluded that the volume weight of the composite mixture depends on the fill-in method, which affects the horizontal silage pressures. At filling of 0° and 45°, the pressure is slightly different from Jansen's theory (max 19%) which can be neglectable. Horizontal silage pressures are functionally dependent on the filling method (up to 44%), which should definitely be taken into account.

Flow and clogging in a horizontal silo with a rotary obstacle

The external perturbation applied to a silo and the placement of an immobile obstacle before an exit are two common and effective ways to diminish clogging in the hopper/silo flow. Here, we incorporate the local perturbation into a fixed obstacle, and experimentally explore the effects of a rotary obstacle on clogging and the flowing characteristics in the horizontal silo flow driven by a conveyor belt. Even with a low spin rate, the total blocking probability that a particle constructs a stable blocking arch with its neighbors significantly drops. Correspondingly, the average flow rate of the particles through the exit abruptly rises, at least 1 order of magnitude better than that with an immobile obstacle and approaching the flow rate of continuous flow. The rotation enhances the breakage of clogging arches, which is responsible for improving the flowability in the horizontal silo. In addition, there always exists an optimal obstacle position at which the total blocking probability is minimal and the average flow rate peaks, regardless of the spin rate. Finally, clogging is relieved with the increase of the driving velocity of the conveyor belt, showing a “fast is fast” effect that is opposite to the “fast is slow” effect in other systems such as crowd evacuation and gravity-driven hoppers.

Discharge characteristics of non-gravity-driven powder in horizontal silos

Powder flow inside horizontal silos is essential to ensure the efficient operation of the spacecraft using powder engines under horizontal flight positions. In the present work, the discharge characteristics of non-gravity-driven powder in the horizontal silo were investigated experimentally, with an emphasis on the half cone angle, aeration position, and additional pressure. The experimental results show that the mass flow rate first increases with decreasing half cone angle and then approaches saturation. Aerating at the cylinder was proved to be able to significantly increase the mass flow rate compared with the previous aeration at the cone. Increasing the additional pressure can effectively improve the mass flow rate, but there is a limit value called pressure surcharge limit to maximize the discharge rate. And aerating at the cylinder can further increase the pressure surcharge limit as well as the maximum mass flow rate, which is close to the ideal flow rate based on the liquid-like hypothesis. Finally, an index η is proposed to evaluate the overall flow-promoting effect to determine the optimal aeration position.

Performance Analysis and Quality Evaluation of Wheat Storage in Horizontal Silo Bags.

Wheat still suffers from the problem of traditional storage methods, limited storage capacity, and a high percentage of losses in terms of quantity and quality. Hermetic silo bags are economical and alternative technique to the traditional storage methods. Ten horizontal plastic silos with the capacity of 200 tons/silo were tested and evaluated for eight months of wheat storage. The evaluations included grain bulk temperature, CO2 concentration, fungal and microbial count, insect count, grain moisture content, 1000-grain weight, falling number, and protein content. The results showed that the stored wheat quality was maintained without any significant difference during the storage period in terms of 1000-grain weight, grain moisture content, and falling number, while there were slight changes in protein content and kernel hardness with a decrease of 5.5% and 4.6% at the end of the storage period. There were no statistically significant differences at the sampling location along the length of the storage silos, which confirms the homogeneity of the internal conditions of the examined silo. The grain bulk temperature inside the silos was always lower than the surrounding ambient air temperature. The higher concentration of carbon dioxide inside the silos during the storage period led to a decrease in fungal and microbial count and the presence of dead insects at the end of the storage period.

Static wall pressure distribution characteristics in horizontal silos

The silos are mainly placed horizontally in the powder propellant feeding systems. However, most of the literatures only report the static wall pressure distribution of the vertical silos. In this paper, a FT4 powder rheometer was used to test the flow properties of the materials, and the wall pressure distribution in the test horizontal silo was investigated experimentally. A physical model based on Janssen theory is proposed to describe the wall pressure distribution characteristics effectively. Both experimental results and theoretical predictions show that the wall pressures at different positions of the same section are different, but all increase under the action of additional pressure and decay along the axial direction, indicating that the final axial pressure is close to zero. In addition, the increase of particle size also leads to the increase of wall pressure.

Comparing the effects of silage and hay from similar parent grass forages on organic dairy cows’ feeding behavior, feed intake and performance

While ensiling is globally the predominant forage preservation method, feeding hay as the sole source of forage has re-emerged in alpine, grassland-based dairying. Studies have shown that many factors could modulate the effects of the forage conservation method on cows’ responses, such as plant species, stage of maturity, cutting and wilting time, and forage cut length. In the present study, forages were obtained from the same fields (grass-dominated swards), mowed at the same time, and treated equally during wilting (roughly for 28 h; 56% DM at harvest). Windrows were harvested alternately using a loading wagon set to a specific cut length (8 cm), either for ensiling in a horizontal silo or barn-drying using an air dehumidifier. Nine months later, 2 feeding groups, with 9 cows each, were offered either one or the other of the conserved forages ad-libitum along with a fixed allocation of concentrate per cow (3.6 kg/d; DM basis) over a period of 34 d. Assignment of cows to groups was based on previous milk yield, body weight, DIM, and parity. Data collection started after a 14-d adaptation period. Data for covariate adjustment of chewing behavior, feed intake, milk performance parameters, and body weight were collected during a period of 9 d, prior to experimental feeding.Results revealed that the cows fed hay tended to increase forage DM intake (18.3 versus 17.8 kg/d; P = 0.07) and ingested a higher amount of water-soluble carbohydrates (+1.2 kg/d; P < 0.01). Hay-fed cows showed a trend towards a greater milk energy output (30.1 versus 28.5 kg energy corrected milk/d; P = 0.09) mainly due to an elevated milk fat yield (1.26 versus 1.16 kg/d; P = 0.02). The total chewing times in both groups were equal, suggesting that the physical effectiveness of fiber was the same, but the fact that cows on hay shortened rumination times per kg of ingested DM (P = 0.02) and NDF (P = 0.01) indicates a greater particle breakdown while eating. Cows on silage tended to sort against CP (P = 0.06) and had a significantly (P = 0.01) looser consistency of feces, but the DM contents did not differ (P = 0.15) when compared with those of hay-fed cows.It can be concluded that grass forages conserved as hay, rather than silage, were more attractive for cows and led to a higher milk energy output. Besides the preferential intake aspects, it can be assumed that the higher content of water-soluble carbohydrates in hay enhanced ruminal fermentation processes, which in turn provided cows with additional amounts of nutrients and energy.

Association of Horizontal Silo Pad Type, Elevation and Core Depth With Indicators of Silo Ramp Hygiene, Forage Quality, and Digestibility

Association of Horizontal Silo Pad Type, Elevation and Core Depth With Indicators of Silo Ramp Hygiene, Forage Quality, and Digestibility

Inclusion of calcium hydroxide-treated corn stover as a partial forage replacement in diets for lactating dairy cows

Chemical treatment may improve the nutritional value of corn crop residues, commonly referred to as corn stover, and the potential use of this feed resource for ruminants, including lactating dairy cows. The objective of this study was to determine the effect of prestorage chopping, hydration, and treatment of corn stover with Ca(OH)2 on the feeding value for milk production, milk composition, and dry matter intake (DMI). Multiparous mid-lactation Holstein cows (n = 30) were stratified by parity and milk production and randomly assigned to 1 of 3 diets. Corn stover was chopped, hydrated, and treated with 6% Ca(OH)2 (as-fed basis) and stored in horizontal silo bags. Cows received a control (CON) total mixed ration (TMR) or a TMR in which a mixture of treated corn stover and distillers grains replaced either alfalfa haylage (AHsub) or alfalfa haylage and an additional portion of corn silage (AH+CSsub). Treated corn stover was fed in a TMR at 0, 15, and 30% of the diet DM for the CON, AHsub, and AH+CSsub diets, respectively. Cows were individually fed in tiestalls for 10 wk. Milk production was not altered by treatment. Compared with the CON diet, DMI was reduced when the AHsub diet was fed and tended to be reduced when cows were fed the AH+CSsub diet (25.9, 22.7, and 23.1 ± 0.88 kg/d for CON, AHsub, and AH+CSsub diets, respectively). Energy-corrected milk production per unit of DMI (kg/kg) tended to increase with treated corn stover feeding. Milk composition, energy-corrected milk production, and energy-corrected milk per unit of DMI (kg/kg) were not different among treatments for the 10-wk feeding period. Cows fed the AHsub and AH+CSsub diets had consistent DMI over the 10-wk treatment period, whereas DMI for cows fed the CON diet increased slightly over time. Milk production was not affected by the duration of feeding. These data indicate that corn stover processing, prestorage hydration, and treatment with calcium hydroxide can serve as an alternative to traditional haycrop and corn silage in diets fed to mid-lactation dairy cows.

The Experiment of the Clog Reduction in a Plane Silo

The flow of particles may be clogged when they pass through a narrow orifice. Many factors can change the probability of clogging, such as the outlet size, the presence of obstacles and external perturbation, but the detailed mechanisms are still unclear. In this paper, we present an experimental study of reduction of the clogging probability in a horizontal plane silo, which consists of a layer of elastic particles transported on an annular flat plate rotating with a constant angular velocity passing through a hopper structure. We found the exponential distributions of the avalanche size for different sizes of orifice and the power law tails of the passing time between two particles. We did not confirm whether there was a critical size of orifice above which the clogging became impossible. We explored the effect of the obstacle on the probability of clogging: and if we chose a proper obstacle placed at a proper position, the probability of clogging could be reduced by a factor of about seven.

Pressure Independence of Granular Flow through an Aperture

We experimentally demonstrate that the flow rate of granular material through an aperture is controlled by the exit velocity imposed on the particles and not by the pressure at the base, contrary to what is often assumed in previous work. This result is achieved by studying the discharge process of a dense packing of monosized disks through an orifice. The flow is driven by a conveyor belt. This two-dimensional horizontal setup allows us to independently control the velocity at which the disks escape the horizontal silo and the pressure in the vicinity of the aperture. The flow rate is found to be proportional to the belt velocity, independent of the amount of disks in the container and, thus, independent of the pressure in the outlet region. In addition, this specific configuration makes it possible to get information on the system dynamics from a single image of the disks that rest on the conveyor belt after the discharge.

Pressures and deformations of bunker silo walls

To investigate the structural stability of horizontal silo walls, a silo (length, 27 m; width, 9.1 m) with straight panels (length, 3 m; thickness, 0.16 m; height above the floor, 2.05 m) on one side and L-shaped wall panels (length, 4 m; thickness, 0.15 m at the bottom to 0.10 m at the top; height above the foot, 1.85 m) on the other side was constructed on the experimental farm of Ghent University. Displacement, strain and pressure measurements were performed during and after filling the silo with chopped maize. The displacements of the straight and L-shaped wall panels, measured with dial gauges and linear variable displacement transducers, were much higher than those predicted from published load combinations. The maximum measured displacements were 3.5 and 13.1 mm, respectively, for the straight and L-shaped wall panels. Moreover, in contrast with the assumption of perfectly restrained panels, the measurements showed that the panels acted partially like cantilever members. Strains were measured with mechanical deformeters, fibre Bragg grating sensors and strain gauges. The majority of both displacement and strain occurred during the second half of the filling process. When full, maximum strains on the outer surface of the silo wall of −110×10 −6 [dimensionless] and −220×10 −6 [dimensionless] were measured at the lower end of the straight panel and at the lower end of the L-shaped wall panel, respectively. The influence on the displacement as well as on the strain measurements of the presence of a surcharge load acting on the silage was very small. Nevertheless, short but high pressures were registered by the load cells when a surcharge load caused by a tractor and wagon passed near the measurement panel. Beneath a filling height of 1.2 m, the load cells indicated a triangular pressure distribution. For a half-filled silo, the simplified shape of the pressure profile is a triangle with a value at the base of 9.6 h kN/m 2 , h being the filling height in m. For filling heights higher than 1.2 m, a peak value appeared at a height of 1.1 m. Beneath this height, the pressure decreased. A peak value of 23.5 kN/m 2 was measured for a completely filled silo.

Instandsetzung von Gärfutter-Flachsiloanlagen

Practical experiments showed that reconstructing horizontal silo facilities with a second layer of air concrete, which is applied with a newly developed surface finisher, can be a permanent and low-cost cost method.

The Influence of Cement Content and Water/Cement Ratio on the Durability of Portland Cement Concretes exposed to Silage Effluent

This paper outlines the findings of a study on the influence of cement content (275–425 kg/m3) and water/cement ratio (0·45 to 0·75) on the durability of concrete exposed to silage effluent. The test facility exposed concrete specimens to a controlled flow of effluent such that the volume of effluent in each 28 day cycle of exposure simulated one year's volume and expected period of effluent flow at the front of a well-drained 200 t horizontal silo. The relative performance of the concrete mixes was assessed over 10 cycles through measurement of saturated mass loss and surface depth change. The saturated mass loss measurement gave more consistent results. Optimum performance was recorded in concretes of cement content 325 and 375 kg/m3with water/cement ratios of 0·55 and 0·50, respectively. The studies indicate that water/cement ratio is a more critical variable than cement content. Deterioration increased significantly when the water/cement ratio exceeded 0·5. Increasing the cement content beyond the minimum recommended value in current national specifications (350 kg/m3) did not lead to a reduction in mass loss rate. The benefits of high cement content concretes is questioned, therefore, not least because of the increased risk of early-thermal cracking. It is postulated that specifications should limit the maximum water/cement ratio and both maximum and minimum cement content.

A Study of the Effects of Silage Effluent on Concrete: Part 1, Significance of Concrete Characteristics

This paper outlines an experimental facility that was used to study the effects of silage effluent on concrete by simulating the front of a 200 t horizontal silo. An effluent flow rate of 1431 of effluent per m 2 concrete per d and a flow period of 28 d were used to cause the corrosion associated with each year of service. Nine simulated years were studied and the effects on some durability related properties of concrete were assessed. The concrete mix variables studied were the effects of water and cement contents, water-reducing admixtures, pozzolanic admixtures, and the type of coarse aggregate. Only the surface of the concrete was affected by the effluent and it corroded at a rate of about 1 mm per simulated year. The importance of a low water/cement ratio in producing durable concrete was shown. Water-reducing admixtures and pozzolanas showed potential for reducing the deterioration of farm silos. The type of coarse aggregate was important in controlling the surface roughness.

A Study of the Effects of Silage Effluent on Concrete: Part 2, Significance of Environmental Factors

This paper outlines experiments studying the effects of environmental conditions on the deterioration of concrete by silage effluent. Effluent was allowed to flow at a controlled rate over concrete specimens for nine 28-d periods of flow, such that each period simulated 1 year's corrosion at the front of a 200 t horizontal silo. The effects of flow rate, heat, ultraviolet light, air and effluent type were studied. Ultrasonic pulse velocity readings were taken on a silo floor to investigate whether a weakened layer develops in a concrete silo floor prior to dissolution. Silage juice taken from silage in contact with the concrete floor and from silage 1 m above the floor of five farm silos was analysed and compared. The ultrasonic pulse velocity readings showed no evidence of a weakened layer beneath the corroded surface. The analysis of silage juice showed that the environment in the silage adjacent to the concrete floor becomes non-aggressive to concrete due to secondary clostridial fermentation. It was concluded that this was an important factor in silo durability which could explain the reduced corrosion occurring in concrete under silage, compared with concrete not covered by silage, in the same silo. The duration of effluent flow was considered to be very important in determining when secondary fermention could occur. It was also concluded that effluent type and flow rate could play a lesser role in determining the aggressiveness of the environment in different silos.

Effects of dry-matter content on the nutritive value of individually wrapped round-bale timothy silage fed to sheep

Thirty-two sheep (30.0 kg avg. BW) were used to study the effects of dry-matter (DM) content at harvest on the nutritive value of timothy grass silages conserved as round bales of high (52.1%, DM50), medium (39.9%, DM40) and low (23.1%, DM25) DM. Chopped grass of 24.4% DM conserved in a horizontal silo (HS) was used as a control. Gross energy, crude protein (CP) and acid detergent fibre (ADF) contents were similar for all silages (P &gt; 0.05). Neutral detergent fiber (NDF) contents decreased as DM of the silages decreased (P &lt; 0.05). Acid detergent lignin and ash contents were highest in HS and lowest in DM40 silages (P &lt; 0.05). Silage pH and water-soluble carbohydrates decreased with decreasing DM of the silages (P &lt; 0.05), while ammonia-N and lactate levels increased (P &lt; 0.05). Acetate concentrations in round bales were lower than in HS silage (P &lt; 0.05). Significant butyrate concentrations were detected only in DM25 silage. Round-bale silages were chopped before feeding and fed ad libitum. DM intake was 14.5% higher for DM50 and DM40 silages than for DM25 and HS silages (P &lt; 0.001). Average daily gain and feed efficiency were higher for high-DM silages than for DM25 and HS silages (P &lt; 0.01). Apparent digestibilities of NDF, cellulose and crude fiber of the silages were similar, but DM, organic matter, energy and hemicellulose digestibilities were higher for HS than for DM25 silage. Apparent digestibilities of ADF and CP were higher for high-DM silages than for DM25 and HS silages (P &lt; 0.04). The results indicate that to obtain good-quality silage, the DM content of round bales should be 40–50%. The better performance obtained with high-DM silages was indicative of a more efficient utilization of metabolizable energy for gain. Key words: Round-bale silage, timothy, forage

Vorkommen vonFusarium-Arten und ihren Mykotoxinen auf Silomais

Studies of the occurrence of zearalenone in the cutting surface of a horizontal silo were carried out over 12 days. On all sampling days the silage contained less than 0.1 mg/kg zearalenone (detection limit of the thin-layer chromatographic procedure). Zearalenone could not be detected in silage put into interim store over a period of 17 days either. The results document that zearalenone-producing Fusarium species have no considerable share in the decay of maize silage.

Studies on the fermentation of chopped sugarcane

The fermentation of freshly harvested and chopped sugarcane (whole plant) was studied using laboratory silos (600 g capacity). The fermentation was accompanied by a rapid drop in pH during the first 24 h. After a storage period of ten days the fermented sugarcane (canelage) contained less than 10% of the original water-soluble carbohydrates (WSC), approximately 9% ethanol (dry weight basis) and 44% more acid detergent fibre (ADF) than did the original sugarcane. Sugarcane (whole plant) that had been allowed to lie in the field for 48 h before chopping and ensilage, contained 37% less WSC than did the fresh cane; the composition of the canelage (ten-day fermentation) prepared from this “wilted” sugarcane was similar to that prepared from freshly harvested sugarcane. Canelage (pH 3.49) prepared (53 days storage) in a commercial, horizontal silo contained (dry weight basis) 0.80% ethanol, 7.29% WSC, 2.68% crude protein, 1.15% acetic acid, 1.60% lactic acid and 42.4% ADF.

A SILAGE CORING DEVICE

The silage coring device consisted of a rotating tube with a sharp smooth cutting edge, and a 12-volt electric motor powered by an automobile battery. The device was used to drill vertical cores from the silage surface to the silo floor. Total dry matter in a horizontal silo was estimated from the core dimensions and dry weight.