Advanced Design

C&R Technologies is dedicated to producing software tools that not only help thermal/fluid engineers produce analytical answers but also product solutions. Whether you are using the nongeometric analyzers or the CAD-based geometric analyzers, you can apply advanced techniques that transcend traditional steady state and transient simulations.

With our advanced techniques, the uncertainties that abound in thermal/fluid modeling can be treated by a combination of calibration to available test data, and a statistical evaluation of the influence of the remaining uncertainties. Automated techniques are available to assist in both tasks. Traditional steady state or transient "point design evaluation" analyses then become a subprocess of a larger system that provides decision support at a higher lever.

Download the Advanced Design Brochure

Parametric Modeling:  Rapid Changes, Sensitivities

  • Use algebraic expressions and spreadsheet-like variables instead of hard-wired numbers as inputs
  • Make rapid and consistent model changes not only between runs, but also during a simulation run
  • Find out how easy and important it is to make parametric variations, to perform sensitivity analyses, and to answer what-if questions

Optimization:  Design Synthesis

  • Size dimensions, select and locate components, and find an optimal design solution
  • Designate variables to be sized or selected, objectives to be met, constraints and limits to be obeyed, and an arbitrarily complex solution procedure with which to evaluate candidate designs. The software automatically searches for the best viable design

Size, Select, Locate, Optimize

Automated Model Calibration to Test Data

  • Adjust uncertainties in a model automatically, correlating to available test data
  • Designate uncertain inputs, limits on their range, when and where to compare to test data, and how to define a "good fit"... the rest is automatic

Critical Design Case Definition

  • Find the combination of input values that yields the worst-case design scenario
  • Determine the hot case and the cold case given ranges of possible dimensions, environments, properties, component efficiencies, etc.

Reliability Engineering:  Uncertainty Analysis

  • Check margins and safety factors for adequacy
  • Given variations in inputs, find the chances that failure criteria will be exceeded
  • Evaluate uncertainties statistically

Reliability Engineering Histograms in CRTech's EZ-XY

Robust Design:  Designing For Reliability

  • Synthesize designs based on reliability
  • Determine allowable tolerances and acceptance criteria

Avoid Costly Overdesign and Risky Underdesign

Multidisciplinary Design Integration

C&R provides the most comprehensive set of thermal/fluid design and modeling tools available to the heat transfer and fluid flow professional. However, designing reliable products in the shortest possible design cycle time demands inclusion of other engineering specialties such as structures, electric, optics, and cost.

C&R goes beyond intimate interconnections to other software design tools. Our tools are also designed to allow integration into large-scale multidisciplinary design systems and analysis management tools. Contact CRTech for more information on supported interconnections and on developing customized design environments.

Recommended Literature

For more in depth information about our advanced design features please review these CRTech authored technical papers

dispersed vs. coalesced front

Tuesday, June 26, 2018, 1-2pm PT, 4-5pm ET

This webinar describes flat-front modeling, including where it is useful and how it works. A flat-front assumption is a specialized two-phase flow method that is particularly useful in the priming (filling or re-filling with liquid) of gas-filled or evacuated lines. It also finds use in simulating the gas purging of liquid-filled lines, and in modeling vertical large-diameter piping.

Prerequisites: It is helpful to have a background in two-phase flow, and to have some previous experience with FloCAD Pipes.

Register here for this webinar

FloCAD model of a loop heat pipe

Since a significant portion of LHPs consists of simple tubing, they are more flexible and easier to integrate into thermal structures than their traditional linear cousins: constant conductance and variable conductance heat pipes (CCHPs, VCHPs). LHPs are also less constrained by orientation and able to transport more power. LHPs have been used successfully in many applications, and have become a proven tool for spacecraft thermal control systems.

However, LHPs are not simple, neither in the details of their evaporator and compensation chamber (CC) structures nor in their surprising range of behaviors. Furthermore, there are uncertainties in their performance that must be treated with safety factors and bracketing methods for design verification.

Fortunately, some of the authors of CRTech fluid analysis tools also happened to have been involved in the early days of LHP technology development, so it is no accident that Thermal Desktop ("TD") and FloCAD have the unique capabilities necessary to model LHPs. Some features are useful at a system level analysis (including preliminary design), and others are necessary to achieve a detailed level of simulation (transients, off-design, condenser gradients).

CRTech is offering a four-part webinar series on LHPs and approaches to modeling them. Each webinar is designed to be attended in the order they were presented. While the first webinar presumes little knowledge of LHPs or their analysis, for the last three webinars you are presumed to have a basic knowledge TD/FloCAD two-phase modeling.

Part 1 provides an overview of LHP operation and unique characteristics
Part 2 introduces system-level modeling of LHPs using TD/FloCAD.
Part 3 covers an important aspect of getting the right answers: back-conduction and core state variability.
Part 4 covers detailed modeling of LHPs in TD/FloCAD such that transient operations such as start-up, gravity assist, and thermostatic control can be simulated.