Thermally Stratified Tanks

Thermal Stratification of a Cryogenic Tank
Is the tank half empty or half full?

Even optimists have a tough time predicting the pressure within a cryogenic tank, much less sizing pressurant bottles and designing pressure control systems based on complex transient scenarios. If the tank has been left long enough for thermal stratification to appear, it is also tough to predict the temperatures of extracted liquid even though this is often a critical parameter if you need to provide adequate subcooling for downstream pumps.

CFD tools can predict liquid positioning and slow recirculation in the nearly-stagnant ullage (vapor/pressurant) and liquid zones, especially for steady state solutions. They must often compromise thermodynamics (e.g., boiling, dissolution) and are too slow to simulate important transient events like fill, drain, and pressurization. Transient analysis of hours- or days-long stratification isn't feasible.

Flow network codes have difficulty with thermal stratification and with associated natural convection recirculation patterns.

CRTech has unique tools for modeling liquid-filled vessels, including treatment of the large uncertainties involved and all the important physics. We are continuing to develop new methods for handling the special needs of thermally stratified modeling, so check back for updates.

long term storage of LH2
Long-term storage of liquid hydrogen using an internal heat exchanger and vapor-cooled shield

For more information and sample models, please visit our forum post on modeling stratified tanks.

See also: Marine and Aircraft Fuel Tanks, LNG Transport by Rail Car, Cryogenic Design

flow regimes

Introduction to Two-phase Flow

September 24, 2-3pm MDT

This webinar introduces basic concepts in two-phase flow modeling including quality, void fraction, flow regimes, slip flow, pressure drops and accelerations, and heat transfer.

No knowledge of CRTech software is required. However, references to the corresponding FloCAD features will be made to assist users of that product.

Click here to register

Introductory FloCAD Training

Class times: September 5, 10, and 12, 2019, 9:00 am to 12:00 pm MDT daily
Cost: no charge (attendees must have an active support contract)

CRTech will be hosting introductory training for FloCAD (Flow Modeling in Thermal Desktop). This is our standard FloCAD class previously hosted in a classroom environment and now restructured for an online teaching environment.

The class will introduce single-phase fluid modeling concepts and how to build fluid models within the FloCAD work environment. Topics covered include an introduction to fluid modeling components, geometric versus non-geometric modeling options, working with FloCAD Pipes, solution control, and an introduction to path and pipe libraries.

The class will be broken into three two- to three-hour sessions held over a 3 day period. The format will be online lecture and demonstration with opportunities to ask questions. Hands-on lab work will be provided to students to work on after each session. To gain the most from this class, students are encouraged to attend all three sessions.

Prerequisites: Attendees must have basic working knowledge of Thermal Desktop as many of its base features will not be covered in this class but their usage is required for FloCAD.

Eligibility Requirement: This class is a service to our customers. All attendees must have an active support contract. If you are unsure of your support status, please contact CRTech.

Click here to register