Heat transfer—A review of 2005 literature

3D CFD analysis of the effect of inlet air flow maldistribution on the fluid flow and heat transfer performances of plate-fin-and-tube laminar heat exchangers

Heat transfer—A review of 2004 literature

Review of underhood aerothermal management: Towards vehicle simplified models

Cooling system design has a crucial role in defining engine performance and operational limits. Many further improvements can be obtained both in the precision in controlling temperatures of the various engine parts (especially during transient operation), and in the energy consumption of the system. Moreover, the warm-up transient can be relevantly reduced producing benefic effects on vehicle emissions and interior conditioning and comfort. Taking the lead by these considerations, the authors developed an integrated model of an engine cooling system, which is characterized by a complete modularity and permits the simulation of any possible design configuration. The model acts as a “virtual engine cooling system”: its coupling with simple ECU models permits an off-line evaluation of the efficiency of new control strategies, model-based too. In this work a novel model for the engine thermal behavior is proposed to be included in the described modeling architecture. The model so makes it possible permit the simulation of fully transient working conditions including those encountered during engine warm-up.

A Fully Transient Model For Advanced Engine Thermal Management

Heat exchangers used in modern automobiles usually have a highly non-uniform air velocity distribution because of the complexity of the engine compartment and underhood flow fields; hence ineffective use of the core area has been noted To adequately predict the heat transfer performance in typical car radiators, a generalized analytical model accounting for airflow maldistribution was developed using a finite element approach and applying appropriate heat transfer equations including the epsilon-NTU (effectiveness - number of heat transfer units) method with the Davenport correlation for the air-side heat transfer coefficient The analytical results were verified against a set of experimental data from nine radiators tested in a wind tunnel and were found to be within +24 and - 10 per cent of the experimental results By applying the analytical model, several severe non-uniform velocity distributions were also studied It was found that the loss of radiator performance caused by airflow maldistribution, compared with uniform airflow of the same total flowrate, was relatively minor except under extreme circumstances where the non-uniformity factor was larger than 05 The relatively simple set of equations presented in this paper can be used independently in spreadsheets or in conjunction with computational fluid dynamics (CFD) analysis, enabling a full numerical prediction of aerodynamic as well as thermodynamic performance of radiators to be conducted prior to a prototype being built

An analytical study on heat transfer performance of radiators with non-uniform airflow distribution

Use of a Pressure-Based Technique for Evaluating the Aerodynamics of Vehicle Cooling Systems

Wind-Tunnel Tests of Vehicle Cooling System Performance at High Blockage

The high complexity of vehicle front-end design, arising from considerations of aerodynamics, safety and styling, causes the airflow velocity profile at the radiator face to be highly distorted, leading to potentially reduced airflow volume for heat dissi

Vehicle engine cooling systems: assessment and improvement of wind-tunnel based evaluation methods

The high complexity of vehicle front-end design, arising from considerations of aerodynamics, safety and styling, causes the airflow velocity profile at the radiator face to be highly distorted, leading to potentially reduced airflow volume for heat dissipation. A review of the existing experimental techniques for quantifying radiator airflow indicates that currently the most commonly used methods in the automotive industry are propeller based, despite the fact that the accuracy is in doubt, especially when documenting detailed airflow distributions. Two relatively new techniques, including a four-hole dynamic pressure (Cobra) probe and a new pressure-based technique, are presented in this paper. The Cobra probe featured a head size of 1.2 mm and was used to document flow fields in proximity to a section of radiator core in a wind tunnel. The results show that the flow field at the radiator core exit was extremely complex, consisting of jets and wakes. In an investigation of the effect of airflow maldistr...

Eton Y. Ng

Papers

An analytical study on heat transfer performance of radiators with non-uniform airflow distribution

Use of a Pressure-Based Technique for Evaluating the Aerodynamics of Vehicle Cooling Systems

Wind-Tunnel Tests of Vehicle Cooling System Performance at High Blockage

Vehicle engine cooling systems: assessment and improvement of wind-tunnel based evaluation methods

New pressure-based methods for quantifying radiator airflow: