scSTREAM è il software CFD general purpose a mesh strutturata (Structured Mesh) che serve i settori Electronics e Architectural da trent'anni. scSTREAM, in costante evoluzione nel tempo, è caratterizzato dalla velocità di calcolo e dalla semplicità dell'interfaccia utente. Di seguito alcune funzioni che caratterizzano questo software.
Metodi per rappresentare le forme
The shape of a model to be analyzed can be represented by using the following methods: voxel method (slanted faces and curved faces are represented in staircase patterns), cut-cell method (the shape of a model created with a CAD tool can be represented more accurately), and overset mesh method (a model of an arbitrary shape defined with unstructured mesh can be overlapped on a model defined with structured mesh to use the shape created with a CAD tool as is).
Modelli di grandi dimensioni
In structured mesh, even a complicated model does not need to be modified almost at all and the shape or the scale of a model does not affect the difficulty of mesh generation. In addition, Solver performs a calculation at a high speed in parallel computing and achieves effective processing as the speed increases depending on the number of subdomains.
A flow generated by a moving rigid object can be calculated. Conditions including the motions of an object (translation, rotation, and elastic deformation), heat generation/absorption, and air supply/return can be set. The model of a moving object is created on another mesh. In this way, conditions such as the distance that the object moves are limited very little.
Parametric Study Tool is useful to apply multiple conditions to multiple parts and compare the analysis results. The tool automatically performs calculation the required number of times only by specifying the number of conditions and the parameters of the conditions. Multiple analysis results of different conditions can be obtained easily by setting parameters simply at the early stage. In addition, the tool can reduce human errors, which tend to be caused when multiple models are created.
Mesh can be refined partially to represent a model shape more accurately and perform a calculation more efficiently.
Complicated conditions including trigonometric functions and conditional branches such as IF statements can be set without compiling.
The shapes and conditions of frequently used parts can be registered. Conditions include the allocation position, material, and heat generation.
Thermal circuit model
The Delphi model (multiple-resistor model) enables highly accurate calculation.
The performance characteristics of a Peltier-device model can be considered for calculation.
P-Q characteristics and swirling components can be considered for calculation without creating the shape of a fan.
Slit punching model
The pressure loss of a part can be considered for calculation only by setting its opening ratio.
Heat pipe model
Heat transfer from a heat source to a heat-releasing part by using a heat pipe is modeled and the model can be used for calculation.
The shapes of pin fins and plate fins can be created easily by specifying parameters.
The information on temperature of each part and a comprehensive amount of heat release obtained in post-processing of a general CFD analysis is not enough to know the heat path. HeatPathView displays heat paths and the amount of heat transfer in the whole computational domain in a diagram, a graph, and a table, allowing you to find the bottleneck of the heat paths easily.
The tool is provided free of charge (partially optional). The tool can create detailed models of semiconductor packages including QFP, SOP, and BGA by specifying parameters, and simplified models using thermal resistor models such as Delphi models and two-resistor models. Manufacturers of semiconductor packages can provide the data of semiconductor packages as thermal resistor models without releasing the inside information.
Reading wiring patterns
To calculate heat transfer conditions depending on wiring patterns of a printed circuit board (PCB) in detail, the module can read Gerber data output from an electric CAD tool and import the data as a model for a thermo-fluid analysis. By using Gerber data, a more realistic calculation result can be obtained with the consideration of heat transfer affected by an uneven wiring pattern.
By setting temperature difference and emissivity between objects, heat transfer by radiation of infrared rays, for example, can be considered. VF (view factor) method and FLUX method can be used. Transmission, absorption, and reflection of radiant rays can also be considered. The directivity of radiant rays can also be considered in FLUX method.
The software interface supports BIM 2.0. Autodesk® Revit®and GRAPHISOFT ArchiCAD have a direct interface (optional) through which a target part can be selected and the tree structure can be kept and simplified. In addition, the module can load files in IFC format, which is the BIM-standard format
The software can calculate illuminance of various types of light; for example, daylight through an opening of a building and artificial lighting with consideration of its directivity. Object surfaces such as walls are treated as diffusive reflection surfaces. In general, the larger an opening of a building is, the larger heat loss tends to be. Therefore, by calculating the illuminance, the balance between heat and light can be examined collectively.
Air-conditioner parts, CFD parts
The model shapes of parts frequently used for room air conditioning are preset and can be used for simulation. The models include ceiling cassettes, anemostat models, and linear diffusers. The software can import CFD part data, such as air supply characteristics, provided by SHASE* . Various parameters can be set to simulate air-conditioning operation in addition to simple air heating and cooling.
Solar radiation, ASHRAE
Climate data published by ASHRAE is preset and can be used for condition setting. By entering arbitrary values of longitude, latitude, date, and time, the solar altitude and the azimuth angle of the sun at a specified location and time are calculated automatically. The effect of solar radiation can be examined in detail. Various parameters including absorption and reflectivity of solar radiation and materials which transmit light diffusely, such as frosted glass, can be set.
PMV, SET, Ventilation efficiency
Comfort indices PMV and SET can be derived from already obtained temperature, humidity, and MRT (Mean Radiant Temperature) , as one of result-processing functions. The scale for ventilation efficiency (SVE), of which some indices can be converted to a real time, can be set by one click, and the range of calculation area can be selected (for example, either one of two rooms).
Humidity, Dew condensation
The software can analyze humidity in the air. Dew condensation and evaporation on a wall surface due to temperature change can be considered and the amount of dew condensation and evaporation per time can be obtained. The software supports the analyses of moisture transfer inside a solid, and the function can be used to analyze a permeable object and dew condensation inside a part.
Plant canopy model (Flow and heat)
Air resistance caused by plant canopy can be considered by setting the coefficient of friction and the leaf area density. For frequently used plants such as oak tree, their parameters are preset as the recommended values. The software also simulates the cooling effect by the latent heat of vaporization on a leaf surface by using the fixed temperature and setting the amount of absorbed heat. The function can be used for analyses of outdoor wind environment and heat island effect.
Windtool (Batch setting for 16 wind directions)
The tool is to evaluate an outdoor wind environment automatically by using the method proposed by Murakami et al. By specifying a base shape and parameters required for wind environment evaluation, the parameters for 16 directions are calculated and the wind environment is ranked automatically. Detailed distributions of air current and pressure per direction can be visualized.
In addition to fluid force, the effect of an electrostatic field, which applies external force to charged particles, can be considered. By setting electric charge of particles and electric potential of a wall surface, the function can be used for analyses to consider area control of electrostatic coating. Velocity at which charged particles do not adhere on a wall surface can also be examined by using the function.
When a target phenomenon is in a small range and the phenomenon is affected by a wide range of its surrounding area, analysis results of the surrounding area can be used for an analysis of the target phenomenon as boundary conditions to decrease the calculation load. To analyze only the inside of an enclosure for an electronic device highly affected by its outside, the analysis results of the outside can be used as boundary conditions.
Flow of foaming resin
The software calculates the behavior of filling up an object with foaming resin, which is used as a heat insulator for houses and refrigerators. To examine speed and pressure of filling-up and the position for injecting the resin, the software simulates the behavior in 3D. The simulation can provide more pieces of information in shorter time than an actual measurement.
The software calculates the shape of an interface between a gas and a liquid. Either MARS or VOF method can be used, and the calculation target phase can be selected: both gas and liquid, only gas, or only liquid. The function is useful in a wide range of fields: from an analysis of Tsunami in the civil engineering and construction field to an analysis of soldering in the electronic device field.
The phase change between fluid and solid, for example, water to ice and ice to water, can be considered. The following phenomena related to solidification/melting can be considered: change of flow affected by a solidified region, change of melting speed depending on the flow status, and latent heat at melting. A phenomenon that water in an ice maker becomes ice can be simulated using the function.
Joule heat, which is generated when an electric current travels through an object with an electric resistance, can be considered. By setting a wiring of a conductor and specifying values of electric current and voltage, the wiring works as a heat source automatically.
The software simulates the behavior of particles depending on their characteristics (diameter, density, and sedimentation speed) and action/reaction between particles and a fluid. This includes sedimentation due to gravity, inertial force for mass particles, and movement due to electrostatic force, liquefaction at adhering on a wall surface, evaporation and latent heat, the behavior as bubbles in a liquid for charged particles.
Printer paper-feeding model
The software can calculate heat transfer due to paper feeding in a printer. The following phenomena can be considered: Heat conduction by moving paper from a part to another part, heat release from paper to the air, and heat conduction between pieces of paper. This function enables a large scale analysis of a whole printer machine with the consideration of the effect of paper feeding.