Capabilities The features and capabilities of MacroFlow include: Analysis of steady and transient systems Intuitive graphical user interface for easy construction of flow system representations A built-in library of components such as inlets, screens, gas filters, air filters, ducts and tubes, heat sinks, fan-cooled heat sinks, power supplies, fans, card arrays, cold plates, quick disconnects, flow maps, and heat exchangers Ability to modify, extend, and customize flow and thermal characteristics of any component Powerful solution algorithm for fast and robust solution of complex models Visual selection of components for comprehensive post-processing through plots tables, animations, and more Exporting of pictures in various graphical formats and of tables into spreadsheets for further processing, report writing, and presentations Available for Windows 95/98/NT/2000/XP operating systems More details of the various capabilities are provided in the following sections. Integrated Design Environment Extensive Component Library Comprehensive Heat Transfer Capability 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 in Version 2.9 Click here to see the list of enhancements in Version 2.8   Integrated Design Environment MacroFlow’s integrated computing environment for thermal design of electronics systems reflects the way industrial design is conducted. You save time, get designs into prototype stage faster, identify problem areas sooner, and evaluate numerous design alternatives. The MacroFlow modeling architecture builds your system thermal/flow model with: A flexible Graphical User Interface to construct flow networks representing the system layout. A built-in, engineering library of common electronic packaging components. The flow and heat transfer characteristics of the components are taken from handbooks and vendor data; they can also be user-defined. A robust and efficient solver to calculate flow, pressure, and temperature at every critical point in the electronics system package An integrated, post-processing data and visualization suite for examination of results and their communication to team members. Built-in engineering utilities for fast modeling including units conversion, calculated variables, and component libraries for common electronic packaging elements. Click to View Full Size Back to Top Extensive Library of Components for Electronics Cooling Systems and Complex Flow Delivery Applications The component library in MacroFlow contains extensive flow and thermal characteristics of components most commonly encountered in electronics cooling systems and flow delivery systems in semiconductor processing. The characteristics are in the form of accurate pressure drop and thermal resistance correlations that are compiled from various handbooks and vendor-supplied data of off-the-shelf components. Flow Path Elements: Nozzles, intake screens, and exhausts with selectable geometries Straight and screened inlet and exhaust Ducts and zero resistance flow paths Abrupt or gradual area changes, elbows, orifices, valves Junction components including tee, wye, and cross Gas filters used in ultra-high purity gas delivery systems in semiconductor processing with a customizable database that already includes filters offered by Entegris (www.entegris.com) and Mott Coproration (www.mottcorp.com) Electronic Packaging Components: Fans and blowers with a customizable database that already includes products from Dynamic Air Engineering (www.dynamic-air.com), Comair Rotron (www.comairrotron.com), and JMC Products (www.jmcproducts.com). Heat Sinks Fan heat sinks for analysis of pressure drop and cooling in fan-cooled impingement heat sinks Card Passages Air filters with a customizable database that includes characteristics of air filters made by Universal Air Filter (www.uaf.com) Plenums and tanks Heat Exchangers with a customizable database that includes characteristics of products offered by Lytron (www.lytron.com) Cold Plates with a customizable database that includes products offered by Lytron (www.lytron.com) Quick Disconnect (QD) component that accounts for directionality of the flow on pressure drop in QDs and includes characteristics of QDs offered by Eaton Aeroquip (www.aeroquip.com). Flow Map component that allows specification of the characteristics of cooling units (LRUs) in terms of the variation of pressure drop with flow rate and temperature. Power Supplies Generalized heat exchanger model Generic Resistance element for specifying user defined characteristics All thermal and flow information corresponding to a component is user accessible for customization, naming, and storage in a user-defined database. Further, performance curves for nonlinear, or time-dependent data can be added using polynomial, or piecewise-linear data form. Back to Top A Comprehensive Heat Transfer Capability MacroFlow enables accurate prediction of the system temperature distributions in one unified architecture. Calculated variables include the bulk fluid temperature in all flow paths, the average surface temperature of every component, and heat loss/gain. Additionally, a variety of thermal boundary conditions can be modeled such as: Specified heat dissipation or heat flux Environmental heat loss at a specified temperature due to natural or forced convection in combination with radiation Incident external radiation such as the solar flux The thermal resistance considered includes the internal, wall, and external resistances in presence of heat loss to the surroundings. The internal and external heat transfer coefficients can be calculated from empirical or user- defined correlations for forced and natural convection. Back to Top A 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. Then, the specific network characteristics are defined by the user, through tab-dialog input. These component characteristics include volumes, flow resistances, heat transfer coefficients, and any other required properties, all of which can vary with time. 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 is 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 analyze 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 t