Week 1 : Exploring the GUI of GT-POWER

1. GT-SUITE :

GT-SUITE is a single software package for modeling and simulation of systems in automotive and transportation engineering and beyond. It is based on a multi-physics platform, but offers higher level,added-value toolboxes specifically tailored to a continually broadening set of applications:

• Engine performance modeling (including combustion and turbocharging)
• Analysis of measured engine cylinder pressure (combustion profiles)
• Acoustics of intakes and exhausts
• Exhaust aftertreatment
• SiL, HiL and Real-Time simulation of engine, vehicle, and cooling
• Vehicle dynamics (drive cycles, drivelines)
• Hybrid and electric vehicles, fuel cells
• Cooling systems and vehicle thermal management
• Underhood cooling module analysis (3-D solution with COOL3D)
• Lubrication circuits and bearings
• Fuel injection systems
• Hydraulics and pneumatics (valve actuators, brakes, steering, power hydraulics)
• Valvetrain/Camshaft kinematics and dynamics
• Cranktrain kinematics and dynamics (balancing, engine bearings and mounts)
• Crankshaft durability and fatigue
• Chain, gear and belt system dynamics (timing drives)

GT-Suite is an all-in-one package for engineering applications. For example, consider the cooling circuit with a charge-air-cooler & EGR cooler and its link to engine performance; this can be readily analyzed in a single model for analysis & for the design of a combined cooling circuit and engine. 

Graphical Applications within GT-Suite :

1. GT-ISE(Integrated Simulation Environment) :

GT-ISE is the interface where models are built, simulation settings are declared, and simulations (both single and batch) are launched. It is a 2-D environment where various objects are brought into a project map and connected together linking the entire model as a whole.

                                                   Home screen of GT-Suite

To start with running simulations in GT-Suite, there a wide variety of examples available. For example, to simulate the intercooler, it can be opened from tutorials section in the file menu.But to create (or modify) your own model, different components existing in the templates can be dragged and dropped in the workspace. For example, turbine and pump components are added in the existing tutorial of intercooler.

2. GT-SpaceClaim :

GT-SpaceClaim is a tool that can be used to import CAD geometry of various formats, extract volumes and export them for discretization in GEM3D. Building and exporting 3D models of flow systems is also possible.

3. Gem 3D:

GEM3D is a tool that can be used to build 3D models of flow, thermal, and mechanical systems that can be discretized and made into model files for use with GT-SUITE. It provides the ability to build the model in a 3D environment so that the full details of the model can be included. It also includes sophisticated discretization logic that is able to transform the 3D model into a model file that is compatible with the GT-SUITE software. GEM3D can be used to build any system that contains components like pipes, mufflers, manifolds, air boxes, heat exchangers, underhood, cabin, batteries, crankshafts, etc

4. GT-Post :

GT-POST is a powerful data analysis tool used to plot, view, and manipulate data generated either by a GT-SUITE simulation or by an external source. It offers a more efficient data analysis solution than standard spreadsheet software. By employing data pointers, the results viewed in GT-POST are updated automatically and immediately when a model is changed and a simulation is rerun.

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2. Locating the settings :

1. Time control flag

Time control settings is used to define the simulation duration and time-controlling variables. The attributes in this folder must be defined for all simulation.

Time control flag defines the global simulation type with regards to type i.e, whether periodic or continuous.

• Periodic is used for models which contains a periodic event (ex:engine cylinder). The simulation duration for a periodic simulation can be specified in cycles or in time, whichever is most convenient.
•  continuous indicates that the simulation includes no periodic event, and therefore has no need to track results with respect to a cyclic angle.

2. Time step and solution control

They are used to define the numerical parameters for the explicit, implicit, or quasi-steady flow solver.

3. Integrator/ Solver type

Integrator/solver type used in the time-marching of all ODEs including mechanical, electrical and magnetic libraries. Different schemes are available and selected based on the application.

•  Explicit Adams-Bashforth-Moulton predictor-corrector integration scheme with variable order accuracy.
•  Explicit Runge-Kutta integration scheme that is 5 th order accurate.
•  Implicit Trapezoidal integration scheme that is 2 nd order accurate.
• Implicit Hilber-Hughes-Taylor integration scheme that is 2 nd order accurate.
• Implicit 2-stage Radau integration scheme that is 3 rd order accurate.
• Implicit 3-stage Radau integration scheme that is 5 th order accurate.
• Implicit 3-stage Spectral Deferred Correction (S.D.C.) integration scheme that is 5 th order accurate.

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3. Intercooler simulation tutorial :

 1. RUN SETUP

In this settings, the simulation parameters like simulation run time,etc are specified.

a) Time Control:

Time control settings is used to define the simulation duration and time-controlling variables.The attributes in this folder must be defined for all simulations.

As this model doesn't contain any periodic event, the time control flag is set to continuous.

Automatic Shut-Off When Steady-State - ON indicates that the simulation will be stopped if all steady state convergence criteria have been met. - OFF indicates that no automatic shut-off will be used and the simulation will proceed to the maximum duration.

Maximum simulation duration attribute is used to control simulation duration for continuous models, and can also be convenient for periodic models that should run a defined time (i.e. a transient event).A simulation may stop prior to the maximum simulation time if the simulation has reached steady-state and the Automatic Shut-off When Steady State flag is set to on.

Minimum Simulation Duration (Time) attribute may be useful to force the simulation to run a minimum time duration when the Automatic Shut-off When Steady State flag is set to on.This attribute will be ignored when Automatic Shut-off When Steady State flag is set to off.

b) Initialization :

This folder defines the settings about how the initial conditions will be imposed for the simulation. Every state variable must be initialized at time=0.0 of the simulation. For example, flow components must be initialized with pressure, temperature, and composition; flow connections must be initialized with velocity or mass flow rate; shafts must be initialized with rotational speed; other mechanical parts position; and some control components with a "State" value.

Initailization state:

user_imposed indicates that all state variables for each new case of the simulation will be initialized with values imposed by the user. The user-imposed conditions can either come from the values specified in each part in the model (i.e. the attributes for initial pressure, temperature, velocity, speed, etc.) or from the results of a previous simulation

Part Attributes

This option will initialize the simulation with the attributes specified in the parts on the model map for every case. This option is only available when user_imposed initialization is selected.

c) Flow control:

This folder is used to define independent flow “circuits” within the model and to specify solver settings related to modeling of flow for these circuits. A circuit is defined as an interconnected group of flow components, typically sharing the same fluid.

Many simulations will have only one flow circuit. In this case, it only necessary to use the first column, leaving the Part Name List Object Identifying Circuits Belonging to Column set to "def".

d) ODE Control

This folder is used to define independent “ODE circuits” within the model and to specify solver settings related to these circuits. An ODE circuit can be an interconnected group of mechanical, electrical, magnetic, or control parts.

For many simulations, no changes will be required to the prefilled settings in this folder, even if the model includes multiple mechanical or control circuits. But the folder provides the ability to define separate circuits if needed and to change the solver ODE settings for any ODE circuits.

e)Signal Control

f)Thermal Control

This folder controls the thermal wall (structure) solver only, which includes the wall material of pipes and flowsplits, thermal mass/block/node, aftertreatment, and finite element objects. This folder does not control the thermal calculation of the fluid, which cannot be disabled.

Thermal Wall Solver - automatic indicates that the Thermal Wall Solver for pipe/flowsplit walls and other thermal masses will be automatically selected. The automatic solver will choose between steady and transient based on the selection for Automatic Shut-Off When Steady-State from Run Setup -> Time Control. If auto shut-off is " on", then the steady Thermal Wall Solver will be used. If auto shut-off is " off" the transient Thermal Wall Solver is used. 

g)ConvergenceRLT

This folder can optionally be used to impose one or more steady state criteria (up to a maximum of 10) that depend on RLT variables in a simulation.

2. Advanced Setup :

3. Output setup :

In this setting, the parameters regarding the outputs are specified.

a) data storage:

This folder can be used to optionally suppress certain GT-SUITE output in simulations where not all results are interesting. These options can be especially useful for models that are very large (i.e. many parts), span very long durations (i.e. many cycles), or have many cases.

4. Plot Setup:

In this setting, the parameters regarding the plots are specified.

Plot Setup, which is found under the "Run" pull-down menu, gives the user a variety of options to change the way in which the plots are requested.

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4. Problem: (50 Marks)

    Given

• Diameter of cooler inlet and outlet pipe= 50 mm
• Length of the CAC= 1000 mm

• Inlet mass flow rate = 1200 kg/ h at 100 degC

• Outlet pressure 2 bar at 30 deg C

Results:

• Calculate the Average heat transfer at the Charge air cooler (CAC) - 6.11KW

• Calculate pressure drop across CAC - 1.23e-6 bar

Conclusions:

• Thus the GUI of GT Suite format is being explained
• Locations of the different setups is found.
• Elaboration of the different setups is done and explained them.
• For the Intercooler Engine the Temperature and Pressure Drop has been computed.