Search Results

This paper describes the need for dynamic (transient) simulation of automotive air conditioning systems, the reasons why such simulations are challenging, and the applicability of a general purpose off-the-shelf thermohydraulic analyzer to answer such challenges. An overview of modeling methods for the basic components are presented, along with relevant approximations and their effect on speed and accuracy of the results.

Thermal analysis is typically performed using a point design approach, where a single model is analyzed one analysis case at a time. Changes to the system design are analyzed by updating the thermal radiation and conduction models by hand, which can become a bottleneck when attempting to adopt a concurrent engineering approach. This paper presents the parametric modeling features that have been added to Thermal Desktop™ to support concurrent engineering. The thermal model may now be characterized by a set of design variables that are easily modified to reflect system level design changes. Geometric features, optical and material properties, and orbital elements may all be specified using user-defined variables and expressions. Furthermore, these variables may be automatically modified by Thermal Desktop's optimization capabilities in order to satisfy user-defined design goals, or for correlating thermal models to test data.

Over the past 15 years, the industry standard tool for thermal analysis, SINDA, has been expanded to include advanced thermodynamic and hydrodynamic solutions (“FLUINT”). With the recent culmination of the unique modeling tools that are described in this paper, and with concurrent expansions described elsewhere (Ref 1), SINDA/FLUINT has arguably become the most complete general-purpose thermohydraulic network analyzer that is available. These advances have enhanced the usage of the code in the areas of liquid propulsion, fire suppression, and environmental control systems (ECLSS), providing for the first time a common framework for analysis and data exchange between engineers in these otherwise distinct specialties.

This paper describes revolutionary advances in SINDA/FLUINT, the NASA-standard heat transfer and fluid flow analyzer, changing it from a traditional point-design simulator into a tool that can help shape preliminary designs, rapidly perform parametrics and sensitivity studies, and even correlate modeling uncertainties using available test data. Innovations include the incorporation of a complete spreadsheet-like module that allows users to centralize and automate model changes, even while thermal/fluid solutions are in progress. This feature reduces training time by eliminating many archaic options, and encourages the performance of parametrics and other what-if analyses that help engineers develop an intuitive understanding of their designs and how they are modeled.

SINDA/FLUINT (Ref 1, 2, 3, 4, 5 and 6) is a computer program used to analyze thermal/fluid systems that can be represented in finite difference, finite element, or lumped parameter form. In addition to conduction and radiation heat transfer, the program is capable of modeling steady or unsteady single- and two-phase flow networks, their associated hardware, and their heat transfer processes. Because it is generalized, versatile, and user-extensible, SINDA/FLUINT is a standard in the aerospace industry for modeling thermal control systems. It is also used in the automotive, aircraft, electronics, petrochemical, HVACR (heating, ventilation, air-conditioning, and refrigeration), and process industries. C8R's SinapsPlus™ is a complete graphical user interface (pre- and postprocessor) and model debugging environment for SINDA/FLUINT (Ref 7, 8). SinapsPlus also supports the C and C++ languages in addition to the traditional choice of Fortran for concurrently executed user logic.

SINDA/FLUINT (Ref 1, 2) is a computer program used to analyze thermal/Fluid systems that can be represented in finite difference, finite element, or lumped parameter form. In addition to conduction and radiation heat transfer, the program is capable of modeling steady or unsteady single- and two-phase flow networks, their associated hardware, and their heat transfer processes. Because it is generalized, versatile, and user-extensible, SINDA/FLUINT is a standard in the aerospace industry for modeling thermal control systems. It is also used in the automotive, aircraft, electronics, petrochemical, HVACR (heating, ventilation, air-conditioning, and refrigeration), and process industries. C&R's SinapsPlus™ (Ref 3), a replacement for SINAPS, is a complete graphical user interface to SINDA/FLUINT. SinapsPlus is a schematic-oriented pre- and postprocessor that brings modern visualization methods to a simulation code that lacks geometric constraints.

SINDA/FLUINT (formerly SINDA '85) is a computer program used to analyze thermal/fluid systems that can be represented in finite difference, finite element, or lumped parameter form. In addition to conduction and radiation heat transfer, the program is capable of modeling steady or unsteady single- and two-phase flow networks, their associated hardware, and their heat transfer processes. Because it is generalized, versatile, and user-extensible, SINDA/FLUINT is a standard in the aerospace industry for modeling thermal control systems. It is also used in the automotive, aircraft, electronics, petrochemical, and process industries. SINAPS™ (SINDA Application Programming System) is a complete graphical user interface to SINDA/FLUINT. SINAPS is a schematic-oriented pre- and postprocessor that brings modern visualization methods to a simulation code that lacks geometric constraints.

SINDA/FLUINT (Systems Improved Numerical Differencing Analyzer / Fluid Integrator, formerly SINDA '85) is a computer code used to analyze thermal/fluid systems that can be represented in finite difference or lumped parameter form. In addition to conduction and radiation heat transfer, the code is capable of modeling steady or unsteady single- and two-phase flow networks, their associated hardware, and their heat transfer processes. Because it is generalized, versatile, and user-extensible, SINDA/FLUINT is a standard in the aerospace industry for modeling thermal control systems. It is also used in the automotive, commercial aircraft, electronic packaging, petrochemical, and process industries. SINAPS (SINDA Application Programming System) is a complete graphical user interface to SINDA/FLUINT. SINAPS is a schematic-oriented pre- and postprocessor that brings modern visualization methods to a simulation code that lacks geometric constraints.

Capillary pumped loops (CPLs) have undergone extensive development since the late 1970's, and represent a maturing technology that is beginning to appear in spacecraft designs (COMET, EOS AM). Perhaps because most CPL literature is intended for CPL and heat pipe developers, or perhaps because of the myriad of component design and layout options available, many thermal control designers are either unfamiliar with the capabilities offered by CPLs, or are confused about their limitations. This survey paper is targeted toward thermal control designers who must decide when and where to use CPLs, or having chosen a CPL solution, must deal with system-level integration and test issues.