SGER-Exploratory Research with Constructal Theory: Vascular Designs

Duke University, Durham NC

Investigators

Abstract

Proposal Title: SGER-Exploratory Research with Constructal Theory: Vascular Designs Principal Investigator: Bejan, Adrian Institution: Duke University Proposal No: CBET-0831229 Abstract Nature teaches us that in animal design the arterial blood stream invades and bathes an entire volume (organ, muscle, tissue) as a three-dimensional tree-shaped flow architecture. The arterial and venous blood stream is reconstituted from the same volume as a tree-shaped flow architecture. The arterial and venous blood trees are matched canopy to canopy (the ?canopy? vascularizes the volume). This project shows why and when trees matched canopy to canopy are the most efficient way of bathing (servicing, keeping alive) a three-dimensional volume. The focus is on fundamental design principles, or design as science. This project aims to discover the strategy for assembling, optimizing and constructing complex flow structures, in the time direction of increasing fineness and complexity. This forms the basis for the design of vascularized materials with leaf-like structure and volumetric functionality. The application on which the new method is tried is the volumetric cooling or heating of a three-dimensional body, with applications to the cooling of electronics and the packaging of fuel cells. The winning architectures will be such that they create the best tapestry of peaks and valleys of temperature, with the highest peaks (the hot spots shaved to the lowest possible level). This integrative approach to determining the best configurations for volumetric flow systems promises to unlock the design problem of scaling up (using a small model to predict behavior at large scales), and to shed light on natural phenomena of self-organization and animal organ design. The intellectual merit of this project is that the entire panoply of vascularized designs is based on physics principles that have universal applicability, at all scales. The theoretical view is that all these design phenomena involve global ?flow? architectures that are ?alive? with flows. Sustainable designs are those in which imperfections (flow resistances, costs, danger, choke points) are balanced and distributed optimally throughout the flow territory. This integrative approach leads strategically to maximum global performance, and to the discovery of the flow architecture. With regard to broader impacts, the concept of vascularized flow systems and the principle-based approach to the discovery of global design is applicable at all scales, from nano and microscales (electronics, fuel cells), to human size (body suits, bodies of vehicles). This fundamental approach is applicable across the board, from engineering to biology and geophysics. While it is true that even without such a theoretical paradigm humans react correctly to flow imperfections in the field, typically they react by trial and error, on a piece-meal basis. They react without understanding the larger system and how it is connected to the local issue. This project teaches how to be proactive, with designs (mental viewings) that come from principle, and which benefit from the strong backing provided by all the flow designs of nature, animate and inanimate.