AGITATOR - AN OVERVIEW
Agitators are equipment used to homogenize media inside a tank. They work by rotating immersed impellers at a controlled speed. The work exerted by the impeller induces the flow and shear of the media inside the tank, causing a single or multi-component media to homogenize. Agitators are used in industries to enable proper mixing of liquids, promote chemical reactions inside the equipment, keep homogeneous liquid bulk during storage, increase heat transfer during heating or cooling, disperse immiscible liquids, keep the product in a mixed state until used, blend miscible liquids, and dissolve some solids into liquid. Common types of agitators employed for industrial purposes are Paddle Agitators, Anchor type agitators, Propeller type agitators, Blade type agitators, Turbine type agitators, and Helical Agitators. Helical agitators are a type of mixing equipment consisting of ribs or blades arranged in the form of a helix. This design creates axial motion and vigorous fluid motion inside a vessel. It is often used to mix viscous materials. The helical agitator is commonly used for low Reynolds number industrial mixing. The helical design of these agitators generates high shear rates and ensures thorough mixing of materials with different densities and viscosities. Helical agitators are used in polymer industries and other industries that require the use of quite viscous materials.
SCOPE OF THE PROJECT
The objective of this project is to perform a three-dimensional (3D), transient, multiphase Computational Fluid Dynamics (CFD) analysis of a large-scale helical agitator, approximately 12 meters in height and 3 meters in diameter. The agitator consists of a helical coil driven by a 30 HP motor operating at 24 RPM, designed to facilitate the effective mixing of three distinct types of polymer granules. The CFD analysis aims to investigate the flow behavior, particle movement, and mixing characteristics of the different polymer granules within the agitator. A suitable multiphase modeling approach will be employed to capture the interaction between the granular materials and the surrounding fluid phase, while accounting for the effects of the rotating helical coil on material circulation and distribution. The study will focus on evaluating the mixing process over time, identifying potential regions of poor mixing or material accumulation, and assessing the influence of the agitator's geometry and operating conditions on mixing performance. The transient simulation results will be used to monitor the spatial distribution of each polymer granule type and quantify the progression of mixing toward a uniform composition. The primary deliverable of the project is to estimate the time required to achieve an acceptable level of homogeneity in the mixture under the specified operating conditions. The results will provide valuable insights into the agitator's mixing effectiveness, help identify potential opportunities for process optimization, and support improvements in mixing efficiency and overall equipment performance.
CFD MESH
The computational domain is discretized using a combination of polyhedral and hex-core mesh elements, resulting in a total mesh count of approximately 8 million cells. This meshing approach provides a suitable balance between computational efficiency and numerical accuracy for capturing the complex flow patterns generated by the rotating helical agitator. Local mesh refinement is applied in critical regions characterized by high velocity gradients, complex flow interactions, and significant variations in flow direction, particularly around the helical coil and other geometrically complex features. This refinement helps resolve the flow structures and transient effects associated with the agitator's rotation and the movement of polymer granules. Mesh quality parameters, including skewness, orthogonal quality, and cell distribution, are maintained within acceptable limits in accordance with established CFD best practices. The overall mesh is designed to provide adequate spatial resolution for predicting the multiphase flow behavior, particle distribution, and mixing characteristics while maintaining reasonable computational requirements for the transient simulation.
EULERIAN MULTIPHASE FLOW MODEL
The Eulerian computational fluid dynamics (CFD) model is utilized to simulate the transport of granules alongside the primary air phase, incorporating suitable interaction models for each phase. This model operates with a shared pressure field across all constituent phases, while the momentum and continuity equations are addressed independently for each phase. The Eulerian approach is particularly effective for examining the mixing of granules.
Pressure on the Helicoil
The pressure contours developed on the helicoil during the transient multiphase CFD simulation have been extracted and provided to the client for further finite element analysis (FEA). These pressure distributions represent the fluid dynamic loading exerted on the helicoil due to its rotation and interaction with the surrounding fluid and polymer granules during the mixing process. The pressure contours help identify regions of relatively high and low pressure across the helicoil surface, providing valuable insights into the distribution of fluid-induced loads under the specified operating conditions. These results can be utilized as input loads for subsequent structural analysis to evaluate the mechanical response of the helicoil, including stress distribution, deformation, and structural integrity. Since the simulation employs the Eulerian multiphase model, a common pressure field is shared by all phases. Consequently, the pressure contours represent the shared mixture pressure rather than separate pressure fields for each polymer species. The exported pressure data therefore provide a consistent basis for further structural assessment of the helicoil and support the evaluation of its performance under operating conditions.
VOLUME FRACTION
The volume fraction contour plots and corresponding graphical representations for each polymer granule species provide valuable insights into the mixing behavior and overall efficiency of the agitation process. These results illustrate the spatial distribution of the three granular species within the agitator and help evaluate the progression of mixing throughout the transient simulation. A detailed assessment of the volume fraction distribution is performed at various heights of the agitator to understand the vertical distribution, circulation, and degree of dispersion of each granular species. The contour plots help identify regions of material accumulation, non-uniform distribution, and potential segregation, while the graphical representations provide a quantitative comparison of species distribution across different locations and simulation times. By monitoring the variation in volume fraction with time and height, the mixing performance of the helical agitator can be evaluated, and the progression toward a uniform distribution of the three polymer granule species can be assessed. This analysis also helps estimate the time required to achieve the desired level of mixing homogeneity under the specified operating conditions. The combined evaluation of contour plots and volume fraction graphs provides a comprehensive understanding of the agitator's mixing effectiveness and helps identify potential opportunities for improving mixing efficiency and process performance.
We Got More
Go through All Our Case Studies
CFD analysis of Multi Band Remote Radio Unit
The advent of 5G technology has brought about unprecedented advancements in wireless communications, enabling faster speeds, lower latency, and increased capacity. These advancements are associated with higher power consumption and increased heat generation in the 5G Remote Radio units.Increasing data rates and network densification require radio units to process larger volumes of data, leading to higher power consumption and heat generation. Environmental factors such as ambient temperature, humidity, and exposure to direct sunlight also impact the thermal aspects of the radio units. Read More
Wind Load analysis for multiband 5G Remote Radio Unit with Antenna using CFD
The seamless operation of base station antennas is of utmost importance for efficient and reliable communication networks. However, these antennas are constantly exposed to various environmental factors that can affect their performance and structural stability. Among these factors, wind load plays a significant role. Read More
DEVELOPMENT OF COOLING SOLUTION FOR GaN RF POWER AMPLIFIER
The demand for high-power and efficient radio frequency (RF) power amplifiers has been steadily increasing across various industries, including wireless communications, radar systems, and satellite communication. GaN (Gallium Nitride) technology has emerged as a game-changer in RF power amplification due to its exceptional performance characteristics and advantages over traditional technologies. GaN technology offers higher power density, improved efficiency, and wide bandwidth capability, setting it apart from traditional technologies like GaAs (Gallium Arsenide) or SiC (Silicon Carbide). Read More
Structural analysis for Triband Radio unit with antenna
In this project, we performed FEM analysis to check strength of the triband antenna model for the given load conditions. FE mesh consists of higher-order Tet elements & Hexahedral elements. Mesh size is 2810173 nodes & 1611495 elements. Appropriate contacts are modeled between all the parts in the assembly. FEM analysis is carried out as per the load conditions provided by the customer. We carried out Modal Analysis, Sine sweep Analysis (Harmonic Analysis), Random Vibration Analysis, Shock Analysis, Seismic Analysis, and Wind load Analysis. Read More
Structural analysis for 5G Remote Radio Unit
The advent of 5G technology has revolutionized the telecommunications industry, ushering in a new era of ultra-fast data speeds, low latency, and advanced network capabilities. Amidst this transformative landscape, the 5G Remote Radio Unit (RRU) emerges as a critical component, playing an instrumental role in the deployment and optimization of 5G networks. With 5G networks, RRUs have evolved to handle higher data volumes and faster speeds. They are designed to support an increasing number of devices and provide seamless connectivity even in densely populated areas. These modern marvels are a testament to the incredible progress made in wireless technology. Read More