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Technical Paper

Homogenization Method: A Way to Improve Finite Element Analysis on Brazed Heat Exchangers

To obtain quantitative Finite Element Analysis (FEA) results is becoming a necessity in order to reduce development time and consequently project development cost. To this view a methodology has been developed to simulate brazed thermal exchangers for structural analysis. Brazed thermal exchangers are complex systems made of tubes and fins, presenting intricate geometric details. The modeling of such systems for structural analysis can quickly become very tricky in terms of finite element model size if all the details are taken into account. For these reasons, a homogenization method has been developed for these exchangers to simplify their modeling while retaining their right dynamic behavior. This paper will describe the homogenization method applied on heat exchanger brazed cores. Then, some numerical results will show the efficiency of this method to predict the dynamic behavior of such products and the leading benefits obtained in project development.
Technical Paper

UltimateCooling™ System for New Generation of Vehicle

Today there are more and more heat exchangers located at the front end and vehicles are equipped with higher and higher power engine. In the next few years, front end design of vehicle will have to be deeply modified in accordance with the pedestrian crash test specifications. In this way there is a big packaging problem at the front end to solve. This new UltimateCooling™ system uses only one fluid that is water (coolant) to cool all of engine fluids. The conventional heat exchangers cooled by air become new heat exchangers cooled by water. These new heat exchangers: WCAC, WCDS, WOC and WFC will be moved from front end to under hood. At the front end there is only one multi-temperature radiator providing high temperature and low temperature on demand.
Technical Paper

The Need for an Electrical Water Valve in a THErmal Management Intelligent System (THEMIS™)

In order to improve engine Thermal System Management and fulfill the need of car Manufacturers, VALEO is developing new engine cooling « intelligent » Components and Strategies. The evolution of engine cooling strategies with the introduction of electronics in Fan System like FANTRONIC®, Electrical Water Valve or pump like PUMPTRONIC® is presented here. The use of such controlled actuators helps reducing noise level, pollutant emissions and fuel consumption, as well as improving comfort and engine durability. The comparative tests of several cooling architectures carried out on four Mercedes A Class allow comparison of different types of engine cooling strategies and their impact on oil, coolant and metal temperature.
Technical Paper

Exhaust Heat Exchange Coefficient in a Pipe of an Internal Combustion Engine: EGR Cooler and Passenger Compartment Heating Applications

This study shows the measurement and calculation of exhaust heat exchange coefficient in a pipe of internal combustion engine. A specific exhaust-air heat exchanger has been installed on the exhaust line of engine. The Nusselt-Reynolds correlation has been developed and compared to the steady state conditions. The Convective Augmentation Factor (CAF) is approximately 2 at low Reynolds number and 1 at high Reynolds number. The EGR cooler and the exhaust-coolant heat exchanger for improving the passenger compartment heating have been shown.
Technical Paper

Engine Cooling Multi-Exchanger

Europeans automotive engineers are continuously looking for space reduction in the Front End of new vehicles. Consequently, some automotive suppliers tried to provide more and more compact Engine Cooling Modules. Most of the time, the packaging of the heat exchangers, as optimized as it can be, remains a strong limit to a significant decrease of the module thickness. This study proposes a new module concept, where heat exchangers are physically bound, and subsequently combined in a single part. On this basis, the following benefits are obtained: Packaging reduction of ∼30 % Weight reduction from 5 to 10 % Thermal performances improvements To sustain this purpose, new modules combining engine cooling radiators and A/C loop condensers have been designed and engineered in different core technologies. Those components have been bench tested (plenum to plenum) in comparison to its stand alone equivalent heat exchanger.
Technical Paper

CFD Optimization of an EGR Cooler for Heavy-Duty Diesel Engines

The gas flow and heat transfer in an EGR cooler has been studied using Computational Fluid Dynamics method (CFD). The shell-and-tube cooler is intended for heavy-duty diesel engines EGR cooling applications. The influence of the diffuser shape has been studied with regards to pressure drop, flow distribution across the tube bundle, and heat transfer. Inlet temperature is 250 °C, and flows varies from 100 up to 200 g/s. These results were compared to experimental measurements. The influence of the bundle size and design has also been investigated for two designs. A single tube cooler test bench has also been developed to validate the CFD flow and heat transfer models. In flow temperature measurements are provided. The bigger tube bundle has advantages both in terms of pressure drop and even flow distribution. The mean outlet gas temperature is also decreased by 6% in this case. The design of the diffuser has important consequences on flow distribution and pressure drop.
Technical Paper

Virtual Mock Up of Heat Exchanger in Mechanics

This paper concerns the dynamic behavior of mechanical heat exchangers. After a concise description of a mechanical radiator, in this case an automotive radiator, its actual behavior is discussed through an experimental modal analysis. The paper also presents an original approach, based on Finite Elements, to model mechanical heat exchangers and compares the numerical simulation to experimental investigations. Finally, the feasibility of using a radiator-model to build a simple cooling module model is proven.