Engines and Power Cycles, Turbomachinery and Secondary Flows


Turbomachine Components

System-level analysis of jet and rocket engines, power generation cycles, heat pumps and refrigeration loops, etc. can be made using performance map-based descriptions of single- or multi-stage pumps, fans, turbines, and compressors. These elements predict flows and pressure drops, using either directly input maps (single curves or multiple curves per shaft speed) of flow versus pressure drop, or maps specified using equivalent states, reference states, head and flow coefficients, etc. Isentropic efficiencies may be specified, enabling the code to predict shaft power and hydraulic torque. Tables of flow and efficiency relationships are normally input, but options exist for parametric inputs, functional (algorithmic) descriptions, as well as links to turbomachine design software.

  • Pumps: Reference speeds or flow/head coefficients (to exploit pump similarity laws), cavitation detection and modeling (based on either NPSH or Nss) , viscosity corrections, and two-phase flow degradations. Nonmonotonic curves (with positively sloped regions) are permitted.
  • Turbines: Equivalent conditions, including equivalent speed options available. Handling of choking and truncated tables, and two-phase outlet states. Total-total, total-static, and other inlet/outlet state options. Efficiency may optionally be a function of U/C: the blade tip velocity to isentropic spouting velocity (or fluid jet velocity) ratio. Power (or equivalent power) may be specified instead of efficiency.
  • Compressors (Variable displacement): Equivalent conditions, including equivalent speed options available. Handling of choking and surge regimes. Total-total, total-static, and other inlet/outlet state options. Power (or equivalent power) may be specified instead of efficiency. Nonmonotonic curves (with positively sloped regions) are permitted.
  • Compressors (Positive displacement): Flow specified via volumetric efficiency (versus speed and/or pressure ratio) and displacement volume. Power may be specified instead of isentropic efficiency.

Engines and Cycles

Design and analysis of engine or power cycles can include single- or two-phase flow components such as boilers, condensers, regenerative heat exchangers, control valves, etc. in either steady or unsteady analyses. For systems with interconnected turbomachines (e.g., turbochargers, turbopumps, turbojets, etc.), shaft speeds can be predicted to balance torques in steady-states, or shaft/gear mechanical speeds can be solved in transients concurrent with the cycle thermohydraulics.

Secondary Flows

Extensive options exist for modeling passages within rotating machinery, including between rotating and stationary parts. Analysis of secondary coolant, leakage, or lubricating flows can exploit built-in correlations or user-supplied correlations for friction, heat transfer, and torque.

Validation Case

Advanced Liquid Oxygen Turbopump

Additional CRTech Resources

Choking and High-speed Flow

Tuesday December 17th, 2pm MST

When flow velocities get big, things gets interesting. Above Mach=0.1, the bulk fluid "sees" a wall that is warmer than the structural temperature due to deceleration within the boundary layer. Above Mach=0.3, kinetic energy changes cease to be negligible. And of course, nothing moves faster than Mach=1.0 for internal flow. When you also add in changes in flow area, or changes in phase ... well, let's just say that doesn't simplify anything.

This webinar will introduce you to the phenomena involved, with a focus on the FloCAD modeling parameters available and their associated correlations and assumptions.

Click here to register

Turbomachinery and Rotating Passages (Secondary Flows)

Thursday December 19th, 2pm MST

Are turbomachines a component in your system, and you'd like to treat them as a "black box"?

Or are they the focus of your work, and the cycle is just a boundary condition to you?

Either way, this webinar will have something to offer you. Each type of turbomachine will be covered: pumps and fans, positive and variable displacement compressors, and turbines (whether gas or hydraulic). Methods for modeling systems like turbochargers and turbopumps will be introduced. Tools for handling spinning flow passages and rotating cavities will be presented.

Click here to register

Starting in 2020, we will begin offering Introduction to Thermal Desktop and Introduction to RadCAD as either in-person training or online training, alternating between online and in-person every three months. The training uses lectures and demonstrations to introduce you to basic Thermal Desktop and RadCAD usage. Hands-on tutorials provide practice building models and interpreting results (tutorials are completed by students outside of the online class time).
The next training class will be an online format in January 2020:
  • Introduction to Thermal Desktop (and SINDA) - A three-part series on January 14, 16, and 21 from 9am to 12pm, Mountain time
  • Introduction to RadCAD - January 23 from 9am to 12pm, Mountain time
For up-to-date schedules, fees, and policies, visit our Product Training page. To register for the class above, complete our registration form and select "Online" for the Training Format.
If you are interested in product training for your company based on your schedule, please contact us to obtain a quote for training between 8-12 attendees. We can come to your facility or the lectures can be presented online. Descriptions of the available classes can be found in our course catalog.
To keep up with our training opportunities, take a look at our new Events and Training Calendar.