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KULI Newsletter 08/2019

|   Newsletter KULI

KULI 13 & 13.1 Features and Improvements; KULI Coupling and Automation; VTM Services; Sharing experience at KULI User Meeting 2019; Component selection

KULI 13 & 13.1 Features and Improvements

The main features of the latest KULI versions include:

  • Full and consistent 64bit support
  • Extension of the dynamic solver
  • Complete revision of AC solver
  • Reduction of calculation time
  • Handling and Workflow Improvements:
    • Quickly find sources of a signal receiver
    • Filter function in KULI lab project tree
    • 2D charts in KULI lab supports unit change
    • Enhanced message and error logging mechanism

For a full list of features and improvements please refer to the release notes.

 
Full and consistent 64bit support

Since version 10 KULI has been delivered with the KULIAnalysis DLL in both 32-bit and 64-bit versions. With version 13 the DLLs have been replaced with the 64-bit KULIAnalysisServer. KULIAnalysisServer runs separately to the KULI interface or any third-party applications such as Excel or Matlab regardless of bitness. It is more stable and handles memory more efficiently and having one version of KULIAnalysis ensures consistent results regardless of the application using it. Note, however, that simulation results run on Intel Haswell processors and newer models may differ slightly from older 64-bit processors due to the way floating-points are handled in these different architectures. 

 
Extension of the dynamic solver

The dynamic solver now supports the parallel flow cooler (PFC), if the two involved circuits are either water or oil circuits. It is also possible to put one side of the PFC in a dynamic solver circuit and the other side in a classic solver circuit. If the PFC is simulated by the dynamic solver, there are three main differences compared to a simulation with the classic solver:

  • Consideration of fluid volume (as it is done for any component being simulated by the dynamic solver)
  • Different formula for computation of the heat transfer for small or zero flow rates (in order to allow simulation  also for small or zero flow rates)
  • If the heat map is given only for one mode (parallel flow or counter flow) the dynamic solver uses a new and more realistic method to predict the performance of the other mode. The initial temperature can be set separately for the inner and outer side of the PFC.

More information can be found in the KULI online help.

 
Complete revision of the AC solver

The AC solver has undergone a complete revision with the following benefits: 

  • Better stability 
  • Support of more configurations 
  • Better detection of problems caused by questionable data.

In addition system checks and supporting messages have been included to assist the user in finding the cause of incorrect circuit configurations. The online help has been updated to provide guidelines how to set up valid A/C circuits.

More information can be found in the KULI online help.

 

Reduction of calculation time

Reduction of the calculation time when handling user defined formulas in the calculation controller, when using the logging mechanism, and for the evaluation of material properties. 

The effective improvements are strongly depending on the complexity of the models:

  • The tutorial example EX_AC_cool_down_recirc.scs now runs more than 20% faster. 
  • The tutorial example Ex_DrivingSim_JC08.scs with a lot of user-defined functions is improved by 75%.

More information, regarding the changes in the calculation controller, can be found in the KULI online help​​​​​​​

 

Quickly find sources of a signal receiver

In a complex system it can be difficult to trace back the sources of signal receivers to their related components. A context menu item of the signal receiver now allows you to find the source component and center it on the display. This works whether it is included in a sub system or not. If it is visible in the 3D view it will be highlighted as well.

More information can be found in the KULI online help.

 
Filter function in KULI lab project tree

To quickly find and select data series there is a filter available at the top of the project tree. Any text entered in the search field applies a filter on all items in the tree view. Multiple words can be entered separated by a space or a "+" sign “Find Next" and "Find Previous" buttons allow to navigate through the filtered list, selecting items one at a time.

More information can be found in the KULI online help.

 

2D charts in KULI lab supports unit change

In the Axes editor for a 2D chart, in which different properties of the 2D chart can be changed, there is now a possibility to change the displayed unit. After changing the units the chart will be updated with the recalculated values.

More information can be found in the KULI online help.

 

Enhanced message and error logging mechanism

Log files are written during system modelling, simulation and during post-processing in KULI lab. The files can be found in the "%appdata%\ECS\Logs" folder. The KULI log file can also be shown with the menu command “Output -> Show log file”. In addition, a descriptive error message and an entry in the log file are given when the calculation is stopped due to problems with writing the hdmb result file.

More information can be found in the KULI online help.​​​​​​​


KULI Coupling and Automation

KULI provides a flexible and easy way to interface with third-party software. Thus, both very simple and complex co-simulation scenarios can be realized. For example, a larger number of KULI models can be run in parallel in batch mode. Or you couple KULI with other simulation models in a complete vehicle simulation environment.

 

PyKuli - A Python Interface for KULI

For low level (source code based) integration, a Python module was introduced which wraps KULI Analysis to allow an easy automation of KULI in a Python script. The user does not have to worry about how to connect the KULI COM server - this is done by the wrapper. Moreover, the wrapper does not rely on a specific KULI version, but is compatible with KULI 8 and newer versions. To target a KULI version it's only necessary to specify the corresponding version string.

See the following code snippet which utilizes KULI 13.1 to simulate "ExCar":

kuli = KuliAnalysis("13.1")

kuli.kuli_file_name = r"C:\ECS\KULI_131000\data\CoolingSystems\ExCAR.scs"

kuli.initialize()

kuli.simulate_operating_point(0)

kuli.clean_up()

del kuli

More scripts and automation examples, also in other languages, can be found here.

 

KULI Simulink Toolbox

Depending on the software or simulation environment in which KULI is to be integrated, there exist add-ons or extensions that simplify the integration of KULI into these tools. As an example, the KULI Simulink Toolbox integrates a KULI model into Matlab Simulink with only a few clicks. In the latest version of the Toolbox there have been made noticeable enhancements. As an example, it now supports KULI 13 and 13.1 as well as a relative path definition for the KULI model file. Furthermore, the UI has been cleaned-up to give you a better usage experience. KULI messages and errors are now (optionally) forwarded to the Matlab console and multiple bugs have been fixed.

The toolbox is free of charge and can be downloaded from the KULI Homepage.

 

KULI FMI/FMU support

The coupling capabilities of KULI are currently extended in the support of FMI/FMU. KULI will then offer the possibility to export a cooling system model as a FMU for co-simulation, following the FMI 2.0 standard. The main focus is set on the simplest possible creation workflow for a FMU. Therefore, the interface of the FMU can be modelled in KULI by using the well-known COM objects. The generation process of the FMU is dialog based and does not require any source code hacking or compilation tasks.

The KULI FMU is self-contained which means that the FMU user does not require a KULI installation on its system. For the simulation a low-cost FMU runtime license or existing KULI simulation licenses can be used.


VTM Services

In addition to our role as software developers, we also offer a wide range of VTM related simulation engineering and development services. Our long-time expertise with 1D and 3D simulation tasks is nicely complemented by our on-site vehicle testing, engineering, system integration and control strategy competences. We also offer capability-setup projects, which are basically regular engineering projects enriched with KULI- and VTM-training contents.

Currently, our VTM services team is supporting both OEMs and component suppliers in Europe, China, Japan and the United States in more than 10 different projects. Ongoing activities range from

  • complete VTM system development projects in hybrid and electric cars to
  • dedicated A/C and heat pump system investigations,
  • underhood air flow simulations and even
  • highly specialized lubrication investigations of motors and drivetrains.

We currently see a growing demand in the development and optimization of combined cooling system and HVAC control strategies, especially in electric vehicles using heat pump architectures. Due to the necessary combination of a wide range of technical competences, these kinds of tasks are complex… but it is important to face the related challenges to achieve energy efficient vehicles fit for future requirements. Therefore, in addition to ongoing development projects, we are also involved in R&D activities for coming technologies.

Another field where we expect interesting innovations and growing demand for simulation is the electrification of off-highway machinery. Emission regulations, acoustic considerations and also currently unused potentials for energy recuperation are strong drivers for this trend. Where currently electrification mostly takes place in smaller construction vehicles, we expect a more widespread use of new technologies in the coming years. And with this, of course, also new VTM challenges will arise.


Sharing experience at KULI User Meeting 2019

In May 2019 we have hosted the International KULI User Meeting in Linz/Austria.

The focus was on the following topics:  

  • System level vehicle thermal management simulation
  • Electric vehicles, hybrids and combustion engine cars
  • Coupled simulation and cooling system control strategies
  • Performance of components, benefit statements and variant investigations

And, of course, we also presented news and updates about KULI and new and exciting applications. But what made our user meeting really special was, once again, the participation of friends, colleagues and customers from a wide range of OEMs and suppliers. We thank everyone for their contributions to many valuable discussions and for the very positive feedback!

You can find the presentations received from experts from Lamborghini, Audi, Air International Thermal Systems, DLR, Tata Motors, Wacker Neuson, Sunamp, Altran Engineering, AVL and of course MAGNA in the download area of the KULI website. Please register to get access. The next national user meetings will take place in India, China, Japan, Korea and USA in 2020. The next international user meeting in Austria will be in 2021. We are looking forward to meeting you there (again).

 

Presentations at upcoming Conferences

Do you want to see our new exhibits and talk to our colleagues about our products and innovations? Take the opportunity to come and speak with us in person! As the year slowly draws to a close, we will use a VDI event in Stuttgart to report on our shared activities in a large EU funded research project about coupled simulation

December, 03/04, VDI Thermomanagement in elektromotorisch angetriebenen PKW, Stuttgart, Germany

 

E-Mobility and Thermal Management Workshop

Before touring China (Shanghai and Beijing) and Japan (Tokyo) in early November, the next European stop of our well established e-mobility workshop is Gothenburg /Sweden.

The following topics will be covered:

  • Electric components (batteries, electric motors, power electronic components)
  • Cooling systems (heat exchangers, pumps, fans)
  • HVAC systems (AC circuit, heater, passenger cabin)
  • Modelling of operating- and driving strategies

Furthermore you will learn how to use KULI lab for a detailed analysis of simulation results, including:

  • Thermal protection of single components and the whole system
  • Range prediction
  • Comfort investigations

This workshop is organized on October 24. It’s free of charge, but a registration on our website is required.


Component selection

The design process of a cooling system always starts with finding the components which fit best to the complete system. KULI can support this step in different ways, which are described here.

 
Easy to get input data for fans

Many fan suppliers are using KULI, which often makes it easy to directly obtain a KULI file for modelling your cooling system. It is well worth to contact your supplier and inquire about available datasets!

Additionally, some fan suppliers are offering the possibility to create KULI files out of their database with the help of an online tool. You usually have to ask for a permission from your contact person to use these tools. Some of the tools that we have already been using ourselves are available online (this list is also available in our online help and will be extended as more tools become available):

Multi-Wing Optimiser axial fan selection software has been developed by Multi-Wing to enable you to select the optimum fan solution for your specific application needs. It can be used as a quick reference guide, and as an advanced tool in the product development process.

Optimiser uses your application requirement data, for instance, airflow, pressure, and power consumption to select a customized Multi-Wing fan solution which matches the required performance calculated by KULI. In addition, you will also be provided with a range of useful mechanical and technical information about the suggested fan solution.  Performance, sound and mechanical data are measured in our wind tunnels in accordance with the AMCA A / ISO 5801 standard.

Optimiser has a built-in KULI export function to allow the selected fan data to be simply imported into KULI. A technical drawing and 3D model of the fan can be created within minutes using the Designer feature to check dimensional suitability in your cooling package. Contact your nearest Multi-Wing sales engineer to activate the Designer and KULI export features, or simply request that our engineers make a fan selection for you – we have more than 60 years’  experience making fan selections.

 

Component search

In your company you probably already have a lot of KULI component files stored in different directories. KULI components offers the possibility to browse and filter these components based on typical project requirements. The following steps show such a process for the example of a radiator:

Let’s assume you are looking for a radiator which should be between 50 and 70 mm in the depth. With KULI components search you have the possibility to find exactly this.  It is possible to search at different file locations and to specify different component types with different criteria. And at the end you’ll get a list of components which fulfills your requirements.

 

Component comparison

Where component search will give you a list of files which fulfill certain design criteria, Component comparison then allows you to understand their differences regarding performance without setting up a test bench or a complete cooling system in KULI. One is able to change the dimensions, flow rates, temperatures and media properties and KULI will show the results in tables or graphs. Of course you can define the units which fit to your requirements. This can help during the process of component selection in a very early project phase.

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