The four functions of elementary pipe design from constructal law (original) (raw)

Novel Aspects of Constructal Law: Four Distinct and Competing Goals in Flow Channels Design

Open Journal of Applied Sciences, 2021

Constructal law explains the sense of evolution (morphing to get access to flows) of finite size systems, but paradoxes do exist as not all vegetables have a tree form. Also, nature does not improve all animals for displacement. This work aims at creating a model to explain those paradoxes about constructal law. It adopted the system engineering technique of segregation between functions (abstract goals) and solutions (physical entities). Further, this work introduced the assumptions of flow under external threats and imperfect channels (subject to leakages and suboptimal form). Results showed that there are always elements doing four functions in all types of channels: to reduce entropy, to protect channel, to retain integrity and to drive flow. Although the four functions are always present, natural systems typically privilege one function over others, depending on environmental demands. As a solution to improve flows, animal brains also fit in the model of four functions. Human mind seems to have groups of instincts associated with each of the four channel design functions, leading to four behavior phenotypes and four motivations (prominence, inclusiveness, negativity prevention and tradition). Finally, this model (channels need to meet four goals) unified physics and animal psychology and extended applications of Constructal law to the fields of systems engineering methods, management, and psychological science.

Constructural theory: The generation of flow-system architecture, from engineering and nature

Ingenieria Mecanica Tecnologia Y Desarrollo, 2005

Making a better design has always been the goal in engineering. A valuable first step is to understand what better means, that is, to see the objective of maximizing global performance, and to feel the global «finiteness» constraints. This step must be made early, before the system configuration (the design) has taken shape. This step frees the designer to think of an infinity of eligible configurations, or to imagine a configuration that morphs freely. Better and better configurations are generated (not assumed), as global performance is pursued under constraints. In this paper I draw attention to an engineering theory on the generation of patterns of «self-organization» in natural flow systems [1-6]. The work of many engineers is in the area of designthe search for better configurations (physical structures) subject to various constraints (e.g., materials, volume, weight, cost), where better is defined by the objective (function, purpose) of the design. The goodness of the design is measured globally, for example, in terms of the energy

Constructal theory of design in engineering and nature

Thermal Science, 2006

This is a brief introduction to an engineering theory on the origin and generation of geometric form in all flow systems: the animate, the in animate and the engineered. The theory is named constructal, and is based on the thought that it is natural for cur rents to construct for them selves in time paths of greater flow access. It is shown that this process of flow path optimization can be reasoned on the basis of principle: the maximization of global performance subject to finite-size constraints. One example is the generation of tree-shaped flow pat terns, as paths of least resistance between one point (source, sink) and an infinity of points (area, volume), as in the circulatory, respiratory and nervous systems. Another is the generation of regular spacing's in heat generating volumes, such as swarms of honey - bees. The optimized tree-flow geometries ac count for allometric laws, e. g., the relation ship between the total tube contact area and the body size, the proportiona...

Constructal Theory: From Engineering to Physics, and How Flow Systems Develop Shape and Structure

Applied Mechanics Reviews, 2006

Constructal theory and its applications to various fields ranging from engineering to natural living and inanimate systems, and to social organization and economics, are reviewed in this paper. The constructal law states that if a system has freedom to morph it develops in time the flow architecture that provides easier access to the currents that flow through it. It is shown how constructal theory provides a unifying picture for the development of flow architectures in systems with internal flows (e.g., mass, heat, electricity, goods, and people). Early and recent works on constructal theory by various authors covering the fields of heat and mass transfer in engineered systems, inanimate flow structures (river basins, global circulations) living structures, social organization, and economics are reviewed. The relation between the constructal law and the thermodynamic optimization method of entropy generation minimization is outlined. The constructal law is a self-standing principle, which is distinct from the Second Law of Thermodynamics. The place of the constructal law among other fundamental principles, such as the Second Law, the principle of least action and the principles of symmetry and invariance is also presented. The review ends with the epistemological and philosophical implications of the constructal law.

Constructal theory of generation of configuration in nature and engineering

Journal of Applied Physics, 2006

Constructal theory is the view that the generation of flow configuration is a physics phenomenon that can be based on a physics principle ͑the constructal law͒: "For a finite-size flow system to persist in time ͑to survive͒ its configuration must evolve in such a way that it provides an easier access to the currents that flow through it" ͓A. Bejan, Advanced Engineering Thermodynamics, 2nd ed. ͑Wiley, New York, 1997͒; Int. J. Heat Mass Transfer, 40, 799 ͑1997͔͒. This principle predicts natural configuration across the board: river basins, turbulence, animal design ͑allometry, vascularization, locomotion͒, cracks in solids, dendritic solidification, Earth climate, droplet impact configuration, etc. The same principle yields new designs for electronics, fuel cells, and tree networks for transport of people, goods, and information. This review describes a paradigm that is universally applicable in natural sciences, engineering and social sciences.

The constructal unification of biological and geophysical design

Here we show that the emergence of scaling laws in inanimate (geophysical) flow systems is analogous to the emergence of allometric laws in animate (biological) flow systems, and that features of evolutionary "design" in nature can be predicted based on a principle of physics (the constructal law): "For a finite-size flow system to persist in time (to live) it must evolve in such a way that it provides easier and easier access to its currents", meaning that the configuration and function of flow systems change over time in a predictable way that improves function, distributes imperfection, and creates geometries that best arrange high and low resistance areas or volumes. This theoretical unification of the phenomena of animate and inanimate flow design generation is illustrated with examples from biology (lung design, animal locomotion) and the physics of fluid flow (river basins, turbulent flow structure, self-lubrication). The place of this design-generation principle as a self-standing law in thermodynamics is discussed. Natural flow systems evolve by acquiring flow configuration in a definite direction in time: existing configurations are replaced by easier flowing configurations.

Special Issue “Configuration and Evolution of Flow Systems”

2012

Natural and engineered flow systems have an intrinsic beauty visible for everybody. They are not amorphous–they have configurations (designs). Concepts and principles of fluid dynamics and heat transfer are fundamental to describe these systems. The ability to understand and predict things is related intimately to the scientific process.