Capabilities MacroFlow enables accurate prediction of the system-level thermo-fluid behavior in a variety of engineering applications. The easy-to-use and integrated Graphical User Interface (GUI) allows quick network construction, solution control, and postprocessing. The component library in MacroFlow is both comprehensive and flexible to enable network analysis of a large variety of engineering systems. Further, a comprehensive database of fluids allows analysis of gas and liquid systems. The heat transfer capability is very complete so that the temperature distribution throughout the system can be predicted for a variety of thermal boundary conditions. Finally, the solution methodology is very efficient, robust, and accurate to ensure reliable use of MacroFlow for system-level design. MacroFlow can be used for the analysis of: Steady or unsteady behavior Compressible (up to choking) and incompressible flow Heat transfer with the surroundings by convection and radiation Real gas properties Mass and energy sources MacroFlow is a productivity tool. It use for the design of flow systems shortens the design cycle, improves the quality of the final design, and reduces the time to market. More details of various capabilities are available in the following sections. Integrated Design Environment Comprehensive Component Library Fluid Property Database Powerful Solution Methodology Comprehensive Post-Processing of Results Capabilities of MacroFlow are being continually enhanced based on modeling needs identified through user feedback. Click on the version number to see the list of enhancements: Click here to see the list of enhancements for Version 2.9 Click here to see the list of enhancements for Version 2.8   Integrated Design Environment MacroFlow provides a unified visual environment for the construction, solution, and evaluation of complex flow systems. The powerful graphical user interface facilitates easy construction of networks, allows flexible control of the solution procedure, and provides graphical display of the results. It enables users to analyze complex flow systems quickly and efficiently. CLICK TO VIEW FULL SIZE To further facilitate network construction, libraries of commonly encountered components, fluids, and units are included in MacroFlow. The flow system is then constructed through mouse driven selection, placement, and connection of the components within the graphical work environment. Solution control parameters, such as relaxation factors, convergence criteria, and matrix-inversion procedure can all be specified through dialogs or pull-down menus. This provides the user with the ability to easily optimize the solution approach for a specific problem. MacroFlow provides flexible post processing through a variety of means, including x-y plots, bar charts, tables, directly on the network, and animation. As with all input fields, units for post processing can be selected from the provided library or user-defined. Once a custom unit has been defined, it is dynamically updated throughout the entire program and added to the unit library. Back to Top Comprehensive and Customizable Component Library An extensive component library is provided with MacroFlow, which includes the following: pipes, ducts, and logical connections elbows, tees, wyes, and crosses with arbitrary angles fans, pumps, and blowers nozzles, exhausts, and intakes with and without screens screens and orifices air filters and ultra-high purity gas filters diffusers and expanders plenums and tanks valves, including pressure, timing, ball, swing, gate, and many more generic resistances customizable node available for Windows 95/98/NT/200/XP operating systems All specific information corresponding to a component is user specified through component dialogs, making network construction simple and easy. Additionally, each component can be customized through a variety of user- defined correlations. Productivity of the thermofluid design of gas and liquid flow systems is further enhanced by including component databases from leading vendors of Gas Filters (Entegris, Mott Corporation) , Heat Exchangers (Lytron), Cold Plates (Lytron), Quick DIsconnest (Eaton Aeroquip), Fans (Dynamic Air Engineering, Comair Rotron, JMC Products), Air Filters (Universal Air Filter), and by providing facilities to extend these databases with user-defined characteristics. Back to Top Fluid Property Database A library of over fifty common fluids and gases is provided with MacroFlow. These fluids occur in a variety of engineering applications such as electronics cooling, semiconductor processing, and fuel delivery systems. These properties are taken from various handbooks such as Thermodynamic Properties in SI by W.C. Reynolds, and Matheson Gas Data Book by Carl L. Lewis. Any other desired operating fluid can be specified through a number of options. Density - Ideal Gas Law, Compressibility Factor, or a polynomial expression Viscosity - Power Law, Sutherland's Law, or a polynomial expression Specific Heat - polynomial expression Thermal Conductivity - polynomial expression Thermal Expansion Coefficient - polynomial expression If the above options are inadequate, a piecewise-linear input mode is available, whereby values of any material property can be expressed in tabular form. Any user-defined fluid property can be saved in the database of fluid properties for ongoing use. Back to Top Powerful Solution Methodology MacroFlow uses the technique of Flow Network Modeling (FNM). In this technique, a flow system is represented as a network of components and flow paths. User can specify the geometrical details of the components for the determination of the component characteristics or directly specify the overall characteristics using the User-Defined option. The FNM methodology is fast because it does not attempt to calculate the detailed variation within a component but it utilizes overall component characteristics. This results in a small number of equations that describe the flow and heat transfer over the entire system which can be solved in a rapid manner. Further, since the component characteristics are empirically determined, the predicted behavior of the system is very accurate. Conservation of mass, momentum, and energy are enforced over the various components and connections. A pressure-correction based solution method has been developed for the analysis of the discretization equations that describe conservation of mass, momentum, and energy over an unstructured network. A direct solution method with Newton-Raphson linearization is used for their solution. The resulting solution method is very fast (solution in less than a minute) and robust. Back to Top Comprehensive Postprocessing of Results Results of analysis of a network model can be examined in a variety of ways as described below: Plots – Predicted variations of various physical quantities can be plotted as Bar Charts or Line Graphs. The appearance of the plots can be customized by specifying the plot color, axis titles, axis range, and font/orientation/format of the captions. Tables – Numerical values of predicted quantities can be listed in tabular format in any user-specifiable units. On-Screen Display of Results – Specific physical quantities of interest can be listed directly on the screen for chosen components to enable convenient examination of the system performance. Animation – The flow of the fluid through the system can be visualized as an animation of colored balls through the network model. Flow animation provides quantitative information because the speed of the dots is proportional to the local flow rate or velocity and the dots are colored according to the local temperature or pressure. Export of Plots and Tables – Both the plots and the workspace can be exported as pictures of a suitable format (bmp, gig, jpg, png, tif) to a user-specifiable file for inclusion in reports and presentations. Similarly, tables can be exported as files of csv format for reading into Excel spreadsheets for further processing of data. In order to facilitate easy creation of the list of components for which results are to be examined using on-screen display, user can visually select the components by first highlighting them on the network before creating plots, tables, or on-screen display of results. The list of components can, of course, be further modified within the individual dialogs. This capability virtually eliminates the need for selecting components by their names, which can be cumbersome for large networks. Back to Top New Features in Version 2.9 Version 2.9 of MacroFlow incorporates new capabilities in the Preprocessor and the Component Library  that enhance its ability to analuze a wider variety of flow systems encountered in many applications including Liquid-Cooled Electronics Systems and Semiconductor Processing. In the following discussion, a summary of these enhancements is provided for users of earlier versions of MacroFlow. Preprocessing Enhanced Library of Gases and Mass Flow Rate Units – Semiconductor processing involves use of inert and reacting gases. The fluid property database of MacroFlow has been significantly enhanced to include the fluid properties (density, viscosity, thermal conductivity, specific heat, and volumetric expansion coefficients) for a variety of gases that are used in semiconductor processing applications. Further, for each gas, units of Standard Volumetric Flow Rate (SCCM, SCFM, SLPM), which actually represent the Mass Flow Rate, are included in the units library. The enhanced library of gas properties and mass flow rate units enables analysis of compressible flow in a wide variety of gas delivery systems in semiconductor applications. Initial Conditions – When MacroFlow is used to perform unsteady analysis, a uniform initial pressure and temperature throughout the systems can now be specified using the Initial Conditions option in the Model menu. This option is activated automatically and only when the model requires transient analysis (e.g. due to time-varying mass flow rate, boundary pressure, and transient filter clogging). By default, the Initial Conditions are set equal to the Ambient Conditions. When heat transfer is inactive, only the initial pressure can be specified with the initial temperature being equal to the ambient temperature.   Enhanced Component Libraries from Leading Vendors – An important capability in MacroFlow is the availability of a Library of component characteristics from the leading manufacturers. Version 2.9 includes characteristics of Quick Disconnect products offered by Eaton Aeroquip (www.aeroquip.com) and ultra high-purity filters offered by Entegris (www.entegris.com) and Mott Corporation (www.mottcorp.com). With this, users can conveniently perform detailed system-level analysis of liquid flow distribution and cooling systems that involve standard QDs and analyze gas delivery systems involving gas filters in semiconductor processing applications. Solver Fan Heat Sink – Impingement heat sinks are commonly used for localized cooling of CPUs that produce high heat dissipation in a small volume. Such a heat sink consists of a fan mounted directly on the top of the heat sink. MacroFlow allows modeling of the flow paths through a fan heat sink where the flow enters at the top of the heat sink and splits into lateral streams after impinging on the base. The flow split can be unequal depending on the flow resistances downstream of each lateral branch. Note that the fan that creates the flow has to be set up separately upstream of the heat sink. The Standard and User Defined options enable analysis in the following manner. Standard – The standard option allows analysis of a plate fin heat sink based on the geometrical characteristics and the thermal conductivity of the heat sink. The flow resistance correlations determine the loss in pressure along each of the two fluid streams that starts at the top of the heat sink and flows out of the side faces. MacroFlow determines the heat transfer coefficient over the fin surfaces, the corresponding fin efficiency, and hence the resulting thermal resistance of the heat sink. By specifying the heat dissipation at the base of the heat sink, MacroFlow also determines the average temperature over the base of the heat sink. User Defined – For a heat sink geometry different than the plate-fin heat sink, the user can specify the resistance characteristics for the flow stream that starts at the top of the heat sink and exits from the side surface of the heat sink. User also specifies the thermal resistance of the heat sink. MacroFlow then calculates the total flow entering the heat sink, the flow split, and the average temperature of the base of the heat sink. Quick Disconnect – Quick Disconnects are used in liquid distribution and cooling systems for convenience in isolating components or subsystems without allowing any leakage. The flow path within a quick disconnect is complex so that the flow resistance characteristics may depend on the direction of the flow. Thus, the flow characteristics can be specified as being independent of or dependent on the flow direction. Each resistance characteristics can be specified as dimensional Polynomial or Piecewise Linear function of the flow rate (volumetric flow rate or mass flow rate) along with the Reference Density and Viscosity at which the characteristics are measured. These characteristic can then be automatically adjusted for changes in density or viscosity of the fluid relative to their reference values. MacroFlow also contains a library of Quick Disconnect products offered by Aeroquip (www.aeroquip.com). Flow Map – Liquid cooling systems used in defense electronics and avionics applications operate under largely varying ambient conditions. Since the properties, especially the viscosity, of the commonly-used coolant fluid varies significantly with temperature, the flow resistance characteristics of the components are significantly affected by change in temperature. A commonly used method of describing the flow resistance behavior is to express the pressure drop as a two-dimensional function of flow rate (mass or volumetric) and temperature. The heat load absorbed by the fluid as it flows through the component is also specified. The temperature used in the representation of the characteristics can be the inlet temperature, the average temperature, or the exit temperature. Note that, such a component characteristics is valid for a specific fluid because the effect of variation of fluid properties with temperature comes indirectly through the dependence of pressure drop on the temperature. When used in the analysis of a system, user has to ensure that the fluid properties are consistent with those used to create the Flow Map characteristics. Back to Top New Features in Version 2.8 Version 2.8 of MacroFlow incorporates new capabilities in the user interface and the component library  that enhance its ability to handle a wider variety of flow systems encountered in many applications including Electronics Packaging, Semiconductor Processing, Automotive Engineering, and Power Systems. In the following discussion, a summary of these enhancements is provided for users of earlier versions of MacroFlow. Preprocessing Ambient Conditions – Boundary components such as Straight Inlet/Exhaust, Screened Inlet/Exhaust, Nozzle, and Boundary Node require specification of ambient pressure and temperature. By default, these conditions are according to the specifications in the Ambient Conditions option in the Model menu. For airflow systems, it is often necessary to account for the effect of elevation on the ambient pressure and temperature. Examples of these include indoor or outdoor air-cooled electronic cabinets operating at high altitudes. To enable convenient accounting of the effect of altitude, MacroFlow now includes a built-in calculation of the variation of the ambient pressure and temperature with altitude. This variation is based on linear decrease of temperature with altitude of 0.0065 deg K/m for the specified sea-level pressure and sea-level temperature as per the International Standard Atmosphere (ISA). Thus ambient conditions are specified using one of the three methods – 1) Direct Specification of Pressure and Temperature, 2) Altitude-based calculation of Pressure with Direct Specification of Temperature, and 3) Altitude-based calculation of Pressure and Temperature. The specification available in Option 2 is suited for airflow systems that operate in controlled environments while Option 3 is suited for specification of ambient conditions for airflow systems that operate in outdoor environments. A sea-level pressure of 1 bar and a sea-level temperature of 15 C used in the International Standard Atmosphere (ISA) constitute the default sea-level conditions in Options 2 and 3. Page Formats and Workspace – User can now set the Orientation and the Size of the page (from which the workspace is built) in the Preferences available in the View menu. Thus, page can be oriented as a Portrait or a Landscape. Also, the page size can be Letter, Legal, A4, and Tabloid. In addition, the maximum number of pages in the workspace has now been increased to 109109 to enable setting up of large network models. Enhanced Vendor Libraries of Component Characteristics - The databases now include characteristics of Fans offered by Dynamic Air Engineering (www.dynamic-air.com) and JMC Products (www.jmcproducts.com), and additional models of Cold Plates from Lytron (www.lytron.com). Solver Gas Filter – Semiconductor fabrication and some of the chemical processing applications require ultra-high purity gases. Therefore, gas-delivery systems in such applications utilize Gas Filters to produce gas streams that are 99.9999999% (9 LRV) free of gas particulates. Such gas filters are typically made of a long and dense fiber plug to capture the particles and therefore involve large pressure drops relative to air filters (represented using the Filter component) used in conventional engineering applications such as outdoor telecom cabinets, ventilation, and automotive applications. The flow characteristic of a gas filter is consists of the following: Pressure Drop – Variation of the pressure drop with the mass or volumetric flow rate is specified. Reference Quantities - The reference values of inlet pressure and temperature at which the flow characteristics are measured and the corresponding molecular weight of the gas also need to be specified for a complete characterization of the flow behavior. The flow behavior of the gas filter at different operating conditions or for flow of a different gas are then determined by correcting the basic flow characteristics for changes in density and viscosity relative to their reference values. Vendor Libraries - A library of the characteristics of gas filters offered by Mott Corporation (www.mottcorp.com) is also included in MacroFlow to enable easy set up of the models for ultra-high purity gas delivery systems used in semiconductor processing applications. User-Defined Flow Resistances for Compressible Flow Systems – MacroFlow allows the user to specify custom flow characteristics using User-Defined Flow Resistance Correlations. The compressible flow calculation in earlier version accounted only for a Minor Loss Coefficient or the Cv factor in user-defined correlations. Version 2.8 now accurately treats resistance characteristics specified in any of the forms (Minor Loss, Polynomial, Piecewise Linear, Power Law, Cv Factor) in compressible flow calculations. Post processing Export of Workspace, Plots, and Tables – MacroFlow now allows exporting of the workspace and plots as pictures for use in presentation documents. Similarly, tables can be exported to Excel spreadsheets for further processing. This is accomplished by using the Export option in the File menu in the following manner: Workspace – To export the workspace, first it needs to be activated by clicking on it. Then, the Export command needs to be invoked. User can choose the format for the picture (bmp, gif, jpg, png, tif) and specify the name of the file to which the picture is written. By default, the Visible Portion of the workspace is captured. However, the user can choose exporting of the Visible Workspace or the Entire Network in the Preferences available under the View menu. Plot – A plot is exported in the same manner as the workspace by first making it to be the active window and then invoking the Export command. User can choose the format for the picture (bmp, gif, jpg, png, tif) and specify the name of the file to which the picture is written. Table – A table is exported to a file by first making the table to be the primary window and invoking the Export command. User can specify the name of the file. The  type of the file is csv so that it can be opened in the Excel spreadsheet. The file contains the component names (row headings), variable names (column headings), and numerical values. 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