Bed Structure Research Articles

Thermal pyrolysis-induced shale micro-cracks: 3D characterization and implication for reservoir stimulation

The geometrical characteristics of thermal cracks at the micro-scale contain valuable information for subsurface enhancing the production of shale oil and gas via in-situ pyrolysis. In this study, six organic-rich shale samples from the Junggar Basin, western China, were thermally pyrolyzed to 250–500 °C, respectively, which were then imaged using X-ray micro-CT. A novel image-processing technique was employed to separate and identify individual cracks that intersect and form 3D networks. Unprecedentedly, over thousands of cracks in each of the volumes were individually characterized by their length, width, thickness, and orientation and then statistically analyzed. It is shown that crack orientations are predominantly parallel to the bedding structures of the shale, different crack networks of the samples represent the heterogeneity of the shale, and the fractal dimension of the crack length ranges from 1.50 to 1.85. All parameters, including porosity, specific surface area, percolation, and the fractal dimension of crack length, show a distinct increase from 350 °C, which is consistent with the threshold temperature for gas generation during thermal pyrolysis. The analysis quantifies the efficacy of pyrolytic stimulation methods and paves the way for developing pyrolysis stimulations for producing shale oil and gas.

Image processing of computed tomography scanned poly-dispersed beds for computational fluid dynamic studies

Achieving our emission reduction goals requires the bulk production of carbon-neutral fuels and chemicals, which are catalytically produced through heterogeneous fixed bed chemical reactors. To optimise and scale-up these reactors, accurate and validated Computational Fluid Dynamics (CFD) models are crucial. Of especial importance to CFD simulations is the accurate depiction of the 3D bed structure used during the experimental setup. A direct one-to-one coupling between experiments and simulations can be achieved by scanning the experimental bed using computed tomography and reconstructing the scanned images as a 3D geometry for CFD simulations. However, processing of the scanned images is necessary to minimise highly coarse features that could impact the overall mesh size. A highly poly-dispersed lab-scale fixed bed reactor, previously scanned and analysed, is processed using various image-processing operations. Depending on the number and the crudeness of the processing operations, the bed is progressively deformed, which impacts both its porosity and its interparticle pore connectivity. The impact of image-processing becomes more evident when the hydrodynamic behaviour, i.e., X-, Y-, and Z-velocity and static pressure, of the beds is explored. CFD simulations revealed highly heterogeneous flow profiles, with the maximum velocity reached being 16-times higher than the average superficial velocity within the bed. Moreover, small modifications in local topological features introduce significant changes to the flow profiles, while the 3D pore interconnectivity was seen to play an equally important role as the interparticle porosity. A particle size study revealed that large particles form less interconnected networks with higher pore volumes, which significantly reduce the flow velocity and the pressure drop experienced by the flow. The generated results yield key insights towards a deeper understanding of the behaviour of fixed bed chemical reactors, highly valuable for catalyst and reactor engineering.

Properties of Packed Bed Structures Formed during Filtration: A Two and Three-Dimensional Model.

Agglomeration is an issue that causes many problems during secondary processing for pharmaceutical companies, causing material to need further processing and costing additional time and resources to ensure a satisfactory outcome. A potential source of agglomeration arises from the particle contacts established during filtration that lead to robust agglomerates forming during drying, so that a necessary first step toward understanding agglomeration is to study the packing properties of filtration beds. Here, we present two and three-dimensional models simulating the formation of packed bed structures during filtration. The models use circular and spherical particles of different sizes, mimicking the bimodal particle size distributions sometimes encountered in industrial practice. The statistics of packing and void formation, along with the distribution of interparticle contacts and percolation structures, are presented and discussed in the context of filtration, drying, and agglomeration. The model paves the way for predictive capabilities that can lead to the rational design of processes to minimize the impact of agglomeration.

Numerically investigation of the neutron irradiation swelling on the mechanical and structural evolution of beryllium pebble bed

Pebble bed is employed in the blanket system to achieve neutron multiplication and tritium breeding. Neutron irradiation among the pebble bed is inevitable when the tokamak device is in normal operation. Particles could be swelled and the formation of bubbles or pore on the surface could aggravate the roughness of particles the surface under irradiation. It has great impact of pebble bed structure. In this paper, the mechanical and structure characteristics of the Beryllium (Be) pebble bed in the Helium Coolant Ceramic Breeding (HCCB) blanket were investigated. Furthermore, the evolution process of the pebble bed with mesoscale is analyzed as well. The Discrete Element Method (DEM) with Particle Flow Code (PFC) software is utilized to simulate the variation of particles under neutron irradiation with different roughness of particle surfaces and irradiation doses. Meanwhile, 0, 1%, 2%, 4% and 6% irradiation of single particle in radius direction with 0, 0.1, 0.3 and 0.5 friction coefficients were assumed. The evolution of the local packing factor, coordination number, contact force and force chain are given, and the fabric analysis is also given. The results show that the irradiation swelling of the particles and the deterioration of the surface have great impacts on the structure and mechanical properties of the pebble bed under neutron irradiation. Particle swelling could improve the packing factor and coordination number of the pebble bed, and the contact force distribution. The deterioration of the particle surface reduces the coordination number and shortens the force chain length. This paper presents the working condition under neutron irradiation which could provide reference for the design and evaluate of the blanket pebble bed.

Topology optimization of catalyst bed structure for a solar steam methane reforming reactor aiming at improved conversion efficiency and hydrogen yield

This study optimized the distribution of catalysts porosity for solar steam methane reforming (SMR) reactor using the topology optimization with different objective functions. The optimized structures were similar, wherein dense catalysts were filled in the high-temperature region at the front of the reactor which increased the contact area between reactants and catalysts, and sparse metal foam catalysts were filled at the rear, which was conducive to reducing the flow resistance and facilitating the collection of products. To facilitate the filling in the actual production process, the optimized structure was simplified, and the simplification structure improved the hydrogen production by 6.84%–22.33% and the methane conversion by 6.54%–11.49% under different working conditions compared with the uniform distribution structure. By adjusting the porosity distribution of the catalysts, the temperature field of optimized reactor conformed to the principle of minimum Gibbs free energy (Gmin) and provided guidance for improving the solar SMR reactor performance.

Landslide risk evaluation and its causative factors in typical mountain environment of China: a case study of Yunfu City

The urban area of Yunfu City is a typical mountain environment with the thin surface soil layer, broken terrain, and the fragile geological environment, which is a landslide hazard prone region, seriously threatening the safety of residents' lives and property. It is crucial to accurately reveal the landslide risk and its causative factors to develop regional geological disaster prediction and mitigation strategies. However, the risk assessment and cause analysis of landslides in Yunfu City are rarely studied at present. Therefore, this study selects 11 causative factors (elevation, slope, slope aspect, bedding structure, distance from fault, lithology, precipitation, distance from water, normalized vegetation index (NDVI), distance from road, and land use), and integrates the modified frequency ratio model and geographic detector method to analyze the spatial distribution pattern of landslide risk and its causative factors. The results indicate that the maximum predicted area under the receiver operating characteristic curve (AUC) and the average predicted AUC of the modified frequency ratio model perform best at the precision of 5, with the values of 0.83921 and 0.81872, respectively, which can accurately reveal the landslide risk evaluation in the study area. According to the experimental results, the landslide risk in the study area generally shows a trend of high in the north and low in the south. Besides, the overall risk of landslide hazards is low, with the area of very low grade and low grade accounting for 75.20% of the total area. Among the selected 11 potential factors, precipitation, NDVI, slope aspect, distance from water and slope are the main causative factors to induce landslide hazards. Furthermore, this study also describes in detail the combination of factors that are conducive to landslide hazards, which can provide a decision basis for relevant departments to carry out regional landslide hazards prevention and mitigation strategies, and can also provide a reference for geological hazard risk evaluation study in other mountain environment.

Comprehensive study on parabolic trough solar receiver-reactors via a novel efficient optical-thermal-chemical model of catalyst packed bed characteristics

The catalyst packed bed structure plays an important role in the promising solar-driven catalyst packed bed based thermochemical hydrogen production systems. However, corresponding accurate yet efficient numerical methods for characterizing and optimizing the catalyst packed bed structure as well as the whole complex solar-driven thermochemical process is still urgently needed. In this paper, a novel three-dimensional comprehensive model is proposed for the hydrogen production of methanol steam reforming reaction (MSRR) in parabolic trough solar receiver-reactors (PTSRR). A relatively realistic porosity distribution obtained by the discrete element method was combined with the optical-thermal-chemical coupling model. The proposed model was validated, proved to improve the accuracy of numerical predictions in a more efficient way. Moreover, it was effectively applied to tune the overall energy flow of the complex optical-thermal-chemical process of PTSRR-MSRRs for better performance, by optimizing the catalyst packed bed structure in aspects of catalyst sizes and packing methods. The results revealed that single packed beds of larger catalyst particles show better performance within the selected catalyst size range. The radial layered packing method of larger particle-to-particle diameter ratios can bring higher energy conversion efficiency and lower flow resistance, as compared to the single packing method and fully mixed packing method. This study could provide an efficient numerical modelling method and significant guidance for other similar solar-driven thermochemical applications of catalyst packed beds.

Comprehensive investigations on flow field in liquid-solid mini-fluidized beds

The Particle Image Velocimetry (PIV) technology was adopted to study the expansion ratio, solid holdup, minimum fluidization velocity, velocity field, turbulent kinetic energy, vortex structure and particle velocity of liquid-solid mini-fluidized beds with bed diameter of 1–3 mm. Due to the wall effect caused by the decrease of bed diameter, the axial velocity at the central axis was 1.68–1.93 times of that near the wall. Both liquid and particle phases had tendency to move toward the central axis of bed. When the liquid velocity gradually increased, the turbulence phenomenon appeared in the liquid-solid mini-fluidized bed. Regarding particles, their axial velocity was mainly influenced by the superficial liquid velocity, while the radial velocity was predominantly by vortices and friction between particles. In this study, the overall movement of flow field was comprehensively obtained, which provided a certain theoretical reference for the design of the liquid-solid mini-fluidized bed reactors.

Design and Fabrication of an Environment Simulation Test Bed for Deep-sea Laser Cladding

The complicated deep-sea high-pressure environment poses a significant challenge for deep-sea laser cladding. To solve this problem, an environment simulation test bed for deep-sea laser cladding is developed in this paper. First, a principle of environment simulation testbed is proposed, which can provide high-pressure water for underwater laser cladding simulation experiments. Based on the principle design, the structure of the environment simulation test bed is modeled in three dimensions, which can carry out underwater laser cladding experiments. Then, the strength of the pressure chamber is analyzed by finite element simulation. Finally, the environment simulation test bed for deep-sea laser cladding is modularly manufactured and integrally packaged. The environment simulation test bed for deep-sea laser cladding can be directly applicable to simulate underwater laser cladding.

Topology Optimization and Analysis of the Compound Boring and Milling Machining Center TX1600g Bed Structure

The overall performance of the machine tool bed of the boring and milling center has an important impact on the accuracy of the overall machining, in order to improve the machining accuracy and structural performance of the overall machine tool, the structure optimization design of the machine bed is carried out for the TX1600g composite boring and milling center. The maximum static displacement and mass of the bed were used as the evaluation index to optimize the topology and structure of the bed. An orthogonal test of 5 factors and 5 levels was designed, the maximum displacement generated by different positions in work was analyzed, the frequency under this working condition was explored, and modal analysis was conducted. The Hyperwork selective variable density method is used to optimize the beam structure with multiple objective topologies. By comparing and optimizing the performance parameters of the front and rear beams, the total static displacement is reduced by 9%, which proves the effectiveness of this method to solve the multi-objective optimization problem.

Numerical simulations of flame spread in pine needle beds using simple thermal decomposition models

Computational fluid dynamics (CFD) models have increased in use for studying scenarios relevant to wildland fires, such as examination of the driving processes in flame spread in vegetative fuels. However, these tools utilize a complex set of submodels which require a large number of input parameters. Often the full set of fuel-specific parameters are not well-quantified and the user must rely upon the best available information. In this study, we examine the implications of using different simple models for thermal decomposition when simulating flame spread through a bed of dead pine needles in quiescent conditions. Model results using one set of common literature values are compared to those using data from milligram-scale characterizations of the fuel. An updated model for char oxidation is also implemented and tested. It was found that the literature values over-predicted mass loss rate by a factor of 2.4, while the fuel-specific values yielded predictions within the experimental uncertainty. A simple approach to decomposition modeling was also shown to be useful for investigating the role of bed structure on flame spread and the heat flux within the fuel bed.

The essential role of initial powder bed state in selective laser melting of 316 L stainless steel

Understanding the essential role of initial powder bed states (e.g., structure and temperature) in the printing process is crucial to obtain high-quality components in powder-bed-based additive manufacturing. In this article, a 3D high-fidelity model which considered the Marangoni effects and recoil pressure was established based on the computational fluid dynamics (CFD) approach to simulate the printing process of 316 L stainless steel through selective laser melting (SLM). The influences of powder bed structure and temperature on the macro- and microscopic characteristics of the molten layer during printing were comprehensively investigated. On this basis, corresponding mechanisms were analyzed. Results show that the developed numerical model can vividly reproduce the SLM process of 316 L stainless steel. With the increase of powder bed thickness from 32.02 μm (Hspreading=2 D90 and Vspreading=0.2 m/s) to 40.65 μm (Hspreading=2 D90 and Vspreading=0.01 m/s), the height of the molten layer will increase from 16.37 to 32.86 μm, the depth will decrease from 21.69 μm to 10.52 μm, and the width will decrease from 100.67 to 94.94 μm. Meanwhile, this will make the fluctuation of the depth (CV) increase from 0.31 to 0.85. When the initial temperature increases from 300 K to 773.15 K, the height, depth and width of the molten layer increase by 3.88 μm, 12.68 μm and 17.37 μm, respectively. In this case, the CV is reduced from 0.34 to 0.23, implying the improvement of the molten layer quality. Under the current laser parameters, the defects such as warping, pores, faults, and balling induced by the insufficient melting in the thick powder bed can to a certain extent be reduced or even eliminated using the high initial temperature. The melting pool collapse will occur in a thin powder bed, the resultant entrained bubble defect in the molten layer can also be properly avoided by the high initial temperature. However, a special groove structure will appear due to excessive energy input. During multi-track melting, the rough surface, irregular molten layer and the pores between the molten tracks are likely to occur due to the insufficient energy input, these problems can be properly solved by employing a high initial temperature.

Experimental Study on Permeability and Deformation Characteristics of Bedding Shale under Triaxial Shear-Seepage Coupling

The bedding structure of shale is generated during the deposition and formation, which results in shales with prominent anisotropic characteristics. It depends on stability, control of oil and gas storage, and deep exploitation. In addition, the mechanical and permeability parts of bedding shale are very complex when it is under deep underground space with coupled high stress and high seepage. In this study, the black bedding shale was used as the research object, and a series of triaxial shear-seepage coupling tests were carried out. Firstly, the triaxial shear stress-shear strain curves and permeability-shear stress curves of different bedding shales under other triaxial shear-seepage coupling conditions were obtained. Secondly, the failure characteristics and shear deformation characteristics of shale under the shear-seepage coupling effect were explored. The shear stress threshold and permeability evolution law at each stage of shear failure were discussed. Thirdly, the shear strength, failure mode, and mechanism parameters of the black bedding shale under different normal stress and seepage pressure were studied. Fourthly, the linear M-C criterion, Ramamurthy criterion, and Hoek-Brown criterion characterize the variation of damage strength of shale with bedding orientation under triaxial shear-seepage coupling. Those results provide an experimental basis for exploring the anisotropic mechanical characteristics and failure mechanism of bedding shale under shear-seepage coupling.

Modified Nursery Structures: An Approach to Grow Rice Seedlings in Winter for Early Spring Planting

Raising rice seedlings in cold winter months for subsequent early spring transplanting has a great challenge in rice-rice cropping system in Nepal. An essential technological intervention involves modifying the rice nursery structure to create an optimal environment that supports proper germination and seedling growth during the cold season. Hence, a field experiment was conducted to evaluate the impact of different nursery structures on the germination and growth of rice seedlings in the farmer’s field at Sunwal-12, Bhumahi, Nawalparasi West, from 21st of January- 19th of February, 2021, 2021. The experiment was executed in randomized complete block (RCB) design with 8 different raised bed (1m × 1m) structures as treatments, namely T1: open uncovered beds, T2: plastic tunnel covered beds, T3: mat bed under plastic tunnel, T4: plastic trayunder plastic tunnel, T5: Plastic tray under open condition, T6: Open bed with removal of dew, T7: Ash covered beds and T8: Plastic sheet covered beds. Each treatment was repeated three times. The spring rice variety Chaite-5 was sown at the rate of 60 g m-2, with dry seeds being evenly distributed in rows spaced 10 cm apart. The beds were fertilized at the rate of 1 kg N, 0.8 kg P2O5 and 0.8 kg K2O 100 m-2. Soil temperatures at a depth of 5 cm were monitored regularly at two time points each day, specifically at 8 am and 4 pm, until 30 days after sowing (DAS). The results revealed that the germination index, average height, and above ground weight were significantly higher (40.57, 9.81 cm and 78.67 gm-2, respectively) for the beds under tunnel (T2). Seedlings grown in trays under tunnel exhibited statistically similar plant heights. The highest seedling population m-2 (288% more compared to open beds) was obtained in trays (both open and under tunnel). Trays and mat beds under tunnel recorded higher soil temperature in the morning and evening, as well as higher air temperatures and relative humidity. These favorable conditions were met approximately 16-17 days earlier compared to the uncovered beds. Therefore, the practice of covering seedling beds with plastic tunnels, growing rice seedlings in plastic trays and utilizing mat beds were the better ways for raising rice seedlings in cold environments for early spring transplanting. DOI: https://doi.org/10.3126/ajn.v7i1.62269

Experimental and numerical investigation on the hydraulic design criteria for a step-pool nature-like fishway

Hydraulic considerations specific for the design of step-pool nature-like fishways (NLFs) are limited to the body dimensions of the target species. Additional hydraulic criteria for flow depth, maximum values for each of pool depth, velocity, and turbulent kinetic energy in terms of the weir opening width and discharge can help design an optimum step-pool NLF. The present study developed design charts and rating curves based on numerical modeling using the computational fluid dynamics software FLOW-3D® HYDRO. Instantaneous velocity measurements on a 1:4 scaled physical model of a step-pool nature-like fishway designed as per the available design guidelines have been used to validate the numerical model. The hydrodynamics of the fishway with respect to the weir opening ratio b r (0.10, 0.25, 0.45, 0.65, and 1.00) and discharge Q (0.1–1.5 m3/s) was analyzed through numerical simulations on a prototype scale. The simulation results showed that the maximum flow velocity and the averaged velocity over the crest at b r = 0.10 and 0.25 are considerably lower than at b r > 0.25. The maximum turbulent kinetic energy and energy dissipation factors for the tested range of discharges were within recommended limits for b r = 0.10 and 0.25. The present study outcome in terms of the design charts and rating curves that illustrate the relationship between different variables can be used for an optimum design and ease in field implementation. In addition, the bed structure of the step-pool NLF presented in this study can be used to recreate full-scale or pilot models.

Petrological Characteristics and Rock Nomenclature of Sedimentary Bauxite Gas Reservoir: A Case Study of Bauxite in Taiyuan Formation of Ordos Basin

With the great breakthrough in natural gas exploration of Paleozoic Taiyuan formation in Longdong exploratory area in the southwestern part of Ordos Basin, it is urgent to solve the petrological nomenclature of sedimentary bauxite, so as to further study the pore formation mechanism, distribution law, and controlling factors of bauxite reservoirs. In this paper, X-ray diffraction, polarizing microscope, scanning electron microscope, and other methods are used to analyze the mineral composition and structure of bauxite rocks in the study area and give appropriate names. The results show that the sedimentary sequence of bauxite in the study area can be divided into five sections: A, B, C, D, and E. The main mineral components are diaspore (C section content can be more than 90%), illite, kaolinite, and chlorite; accessory mineral include anatase and pyrite; trace components include quartz, feldspar, rutile, hematite, and rock salt; and some of the pores are filled with calcite, siderite, and (iron) dolomite. The rock structure is mainly bedding and massive structure, and some of them have geopetal structure. The texture mainly consists of granular texture, grain (powder crystal) texture, gel texture, and algal bonding texture. Considering the special lithology of section A~C and the lack of existing nomenclature method, based on mineral composition and sedimentary fabric, a triangulation classification nomenclature method is established, which adopts structure+texture as secondary name and the main mineral components diaspore-mud-pyrite of the three end-member mineral components as primary name. It can not only highlight the mineral assemblage characteristics of sedimentary sequence of bauxite but also reflect the lithologic characteristics of reservoir development section and the influencing factors of reservoir formation, effectively reflecting the petrological characteristics of bauxite reservoir. Among them, the diaspore rocks with granular, bean-oolitic, and grain texture are the main lithologies forming the natural gas reservoir space of Taiyuan formation in Longdong area. The naming method is feasible and reliable for sedimentary bauxite rocks, which lays a good foundation for the study of natural gas reservoir, pore formation mechanism, and distribution law in Longdong area, southwest of the basin.

Effects of erosional resistance on bedrock channel occurrence and morphology: Examination of the Seo River catchment in South Korea

In tectonically stable regions, bedrock channels develop along deep and narrow valleys that are usually associated with resistant lithology, which enables the transport capacity of these channels to exceed the upstream sediment supply. However, bedrock channels are not restricted to the reaches with a high transport capacity. They are often located in reaches with a lower transport capacity in wide valleys underlain by erodible bedrock. Even though bedrock channels are distributed over a wide range of lithologies, the effects of erosional resistance on the transport capacity required for bedrock channel formation have not been fully clarified. We investigated the bedrock channels in the Seo River catchment in South Korea to determine the relationship between erosional resistance and the occurrence and morphology of bedrock channels. We found that more than half of the bedrock channel segments were in resistant regions. However, a considerable portion also occurred in erodible regions. Most of the bedrock channels in the resistant regions were steep and narrow, generating a higher unit stream power. Therefore, these channels had long stretches of exposed bedrock with actively eroded features such as well-abraded surfaces. In the erodible regions, most of the bedrock channels were wide and gentle, leading to a lower unit stream power. Thus, the exposed bedrock surface was poorly polished, and the channel morphology preserved more of the underlying bedrock's joint or bedding structures. These results suggest that erosional resistance affects the occurrence of bedrock channels by adjusting the threshold stream power required for bedrock incision. Moreover, lithology strongly regulates the bedrock channel morphology in erodible regions.

Similar model test of a mudstone-interbedded–sandstone-bedding rock tunnel

Herein, for the Zhengzhou–Wanzhou high-speed railway mudstone-interbedded–sandstone-bedding rock tunnel, the mechanical parameters of the surrounding rock were tested via uniaxial and triaxial compression tests, and these were converted into rock mass parameters according to the Hoke–Brown theory. Various similar mudstone, sandstone, and tunnel lining materials were prepared in accordance with the similarity theory and orthogonal tests. Based on a similar model test, the effects of the bedding structure and different burial depths on the tunnel lining were simulated. The displacement and contact pressure along the normal direction of the tunnel bedding were evidently greater than those along the tangential direction of the surrounding rock. Further, increasing the burial depth of the bedding tunnel first resulted in longitudinal cracking at the lining invert. Simultaneously, floor heaving occurred in the lining invert, and longitudinal cracks appeared at the lining arch waist corresponding to the normal position of the bedding structure. The similar model test results were found to be in good agreement with the tunnel field test results, indicating that the test model could simulate the mechanical behaviour of bedding rock mass tunnels.

Variation of heat load due to in-vessel debris bed in IVR condition

We performed experiments investigating the heat load imposed on the inner reactor vessel wall in the in-vessel retention of core melt condition, varying the debris bed height and configuration. Mass transfer method was adopted to achieve high RaʹH of order ∼1015 with compact test rigs. We tested three types of the debris configurations: cone, flat and skew debris beds. The results showed that Nusselt numbers decreased in both the uppermost and the curved surfaces with the increasing bed height. Due to the friction increased by the debris bed, the natural convective flow in the oxide pool was weakened, which intensified the impairment of the heat transfer. As the rising plume at the center was disturbed by the porous structure of the debris bed, the local average heat transfer of the uppermost surface was weakened at the center. The heat transfer was dramatically decreased at the curved surface where the debris bed was covered.

Numerical investigation of flow similarity of rice grains in friction rice mill and establishment of scale-up rule

Paddy usually requires a series of processing techniques to become edible polished rice. Among them, rice milling is a necessary processing connection closely related to the nutrition content and economic value of rice. How to accurately control rice milling on demand has always been a frontier topic. In this work, the milling process of rice grains in friction milling cavity with different parameter configurations was simulated numerically. The feasibility of the established simulation model was verified through experiments. Kinematic and dynamic similarity of rice grains in milling cavity were analyzed. The main contribution mechanism affecting the energy loss of rice grains was explored. The scale-up rule that can predict the milling degree of rice was proposed for the first time. The results showed that when the structural or operating parameters change, the flow structure of the particle bed will change significantly, which directly determines rice force characteristics. Besides, the energy dissipation between rice depends more on the configurational temperature dominated by the compactness of particle bed than on the granular temperature. The fluctuation of displacement field of particles will be more intense with the decrease of local space porosity and the increase of external input energy. Finally, a parameter scale-up rule – Relative compaction volume (RCV) suitable for friction rice mill is established. The average dissipated energy of rice grains can be characterized as a linear function of RCV. The characteristic parameter RCV is determined by the geometric characteristics and operating conditions of the rice mill. The research results can provide analytical ideas and theoretical direction for the design and parameter selection of rice mill and similar equipment.