Underhood Cooling Modules

Unique Methodology for Solving the 3-D Flow in Underhood Modules 

An important part of vehicle thermal management is the design of the underhood cooling module (UHM).   This module assembles, in a very confined space, several heat exchangers, stacked in parallel and in series.   It is here that converge the cooling lines from the engine coolant, oil, CAC, EGR, transmission, A/C, etc.   The UHM has to provide the needed cooling to all of these "customers" even at extreme conditions (idling, high altitudes, long climbs, max speed), all exacerbated by hot weather.   It also is called upon to provide fast cabin warmup, and contribute to the goals of lowering fuel consumption and emissions.   Because of all this complexity, the design of the UHM relies extensively on the use of simulations.

The most commonly used methodology for analysis of UHMs is based on 1-D streamtubes, which extend in the main air flow direction along the UHM space.   However, since the 1-D streamtube method does not allow flow in the two cross-directions, it cannot by itself predict the inherently 3-D flow through the module.   Therefore, it always must first be calibrated by time-consuming and expensive wind-tunnel experiments or by 3-D CFD calculations.   Furthermore, any change in geometry, unless it is very small, requires a re-calibration or acceptance of degradation in accuracy.   For this reason it has very limited ability to predict the effects of design alternatives, and it is not well suited for system optimization.

GT-SUITE offers a revolutionary tool COOL3D, based on a modified Navier-Stokes flow solution methodology.   It uses quasi-3D flow elements to achieve a rapid 3-D flow solution.   It is much more predictive than the 1-D streamtube method, and needs very little calibration.   Another advantage is the integration of COOL3D into the entire vehicle thermal management model.   It allows accurate analysis of transient behavior of all relevant vehicle systems as influenced by the UHM design.   As a result, it is well suited for system optimization under steady-state and transient conditions.

COOL3D is a CAD-based tool in which one builds the 3-D underhood module and its space.   In this tool one assembles all of the components of the module, consisting of any number of crossflow multi-pass heat exchangers and fans (complete with shrouds), plus various obstacles, such as the grille, transverse bars, and the engine.   COOL3D automatically discretizes the UHM into a large number of cubes in a fashion similar to CFD, then connects all of the components and exports the model to the flow solver.   The 3-D flow solution is based on the Navier-Stokes equations and is a standard part of the GT-SUITE flow solver.   The solution method is implicit and it produces very fast solutions.

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For more information contact: (or contact us online)
Gamma Technologies, Inc.  601 Oakmont Lane, Suite 220  Westmont, IL 60559  USA	Tel.  (630) 325-5848  Fax. (630) 325-5849 Email: CAE@gtisoft.com Web: www.gtisoft.com

APPLICATIONS

Engine Performance
Test Pressure Analysis
Exhaust Aftertreatment
Acoustics
SiL, HiL, real-time
Vehicle, driveline
Hybrid Vehicles
Cooling/VTM
Underhood Modules

AC and Rankine
Lubrication and bearings
Fuel Injection
Hydraulics, pneumatics
Valvetrain, camshaft
Cranktrain, crankshaft
Chain, gear, belt drive