Physics in Design:Real-time Numerical Simulation Integrated into the CAD Environment

As today's markets are more susceptible to rapid changes and involve global players, a short time to market is required to keep a competitive edge. Concurrently, products are integrating an increasing number of functions and technologies, thus becoming progressively complex. Therefore, efficient and effective product development is essential. For early design phases, in which a large portion of the product cost is determined, it is important that different concepts can be developed and evaluated quickly. An established way of evaluating a design is using numerical methods, such as Finite Element Analysis (FEA). However, setting up numerical simulations in early design phases when concepts change repeatedly is time consuming. This is largely due to the fact that for each design change concepts need to be re-meshed, boundary conditions re-applied and solutions re-calculated. In this paper, a framework is proposed that establishes a real-time connection between the CAD environment and FEA software. Simulation results are automatically updated when the CAD model is updated. Partial re-meshing and smart boundary condition re-application techniques allow for a real-time assessment of design changes. The developed framework is especially interesting for the assessment of multi-physics phenomena in early design phases, as multiple fields can be interpreted by a design engineer that is usually specialized in a specific field

Modelling and performance of heat pipes with long evaporator sections

This paper presents a planar cooling strategy for advanced electronic applications using heat pipe technology. The principle idea is to use an array of relatively long heat pipes, whereby heat is disposed to a long section of the pipes. The proposed design uses 1 m long heat pipes and top cooling through a fan-based heat sink. Successful heat pipe operation and experimental performances are determined for seven heating configurations, considering active bottom, middle and top sections, and four orientation angles (0°, 30°, 60° and 90°). For all heating sections active, the heat pipe oriented vertically in an evaporator-down mode and a power input of 150 W, the overall thermal resistance was 0.014 K/W at a thermal gradient of 2.1 K and an average operating temperature of 50.7 °C. Vertical operation showed best results, as can be expected; horizontally the heat pipe could not be tested up to the power limit and dry-out occurred between 20 and 80 W depending on the heating configuration. Heating configurations without the bottom section active demonstrated a dynamic start-up effect, caused by heat conduction towards the liquid pool and thereafter batch-wise introducing the working fluid into the two-phase cycle. By analysing the heat pipe limitations for the intended operating conditions, a suitable heat pipe geometry was chosen. To predict the thermal performance a thermal model using a resistance network was created. The model compares well with the measurement data, especially for higher input powers. Finally, the thermal model is used for the design of a 1 kW planar system-level electronics cooling infrastructure featuring six 1 m heat pipes in parallel having a long (~75%) evaporator section

Thermal-hydrodynamic modeling and design for microchannel cold plates subjected to multiple heat sources

With advancing electronics, effective thermal management is crucial to maintain optimal performance and prevent overheating. Addressing the challenge of efficient cooling solutions has become a crucial area of research in modern thermal management. This paper applies and validates the Thermal-Hydrodynamic Model to bridge the knowledge gap on how straight, manifold, and serpentine microchannel configurations meet industry standards. The model predicts critical parameters, including electronic package temperatures, temperature differences across packages, thermal resistances, and pressure drops. Findings underscore the effectiveness of the model in accurately estimating thermal resistances and pressure drops within acceptable error margins compared to numerical simulations. Pressure drop estimates for straight channels consistently remain within a 10% error margin. For serpentine microchannels, the error is within 10% when the Dean number is at maximum 40. Manifold configurations, however, do not meet the 10% criterion. For manifold predictions within a 15% error margin, an Inlet Ratio of at most 0.13, a Velocity Ratio of unity, and low Reynolds numbers are necessary. Furthermore, for thermal resistance estimations, a number of grooves of at least 23 is required to maintain 10% validity. Additionally, a case study demonstrates the model's potential as a practical alternative to simulation-based methods for identifying the optimal cold plate configuration, achieving cooling power requirements at least twice as low as other configurations within the design space.</p