Virtual Entropy Generation

Restricted (Penn State Only)
Author:
Zhang, Zhifeng
Graduate Program:
Engineering Science and Mechanics
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
April 07, 2017
Committee Members:
  • Corina Stefania Drapaca, Thesis Advisor
  • Albert Eliot Segall, Committee Member
  • Judith Todd Copley, Committee Member
Keywords:
  • Virtual entropy generation
  • Reliablity and uncertainty control
  • Second-Law of thermodynamics
  • Heat exchanger
Abstract:
The real world is not perfect. So are equations and measurements. In the real world, the first law of thermodynamics is balanced by an error term. At the same time, this error term propagates into the second law of thermodynamics, which causes the so-called virtual entropy generation. The virtual entropy generation is a bridge between the “real-world” and the first and second laws of thermodynamics. Through the inequality of the second law of thermodynamics and measurements, a critical error criterion can be obtained which requires the measurement to satisfy the second law of thermodynamics. The goal of the thesis is to summarize my understanding of the concept of virtual entropy generation. The thesis has three main parts: 1) mathematical descriptions of virtual entropy generation, including its definition and two physical boundaries; 2) a general approach of the virtual entropy generation method, which is expressed in the continuum mechanics framework; and 3) an application of virtual entropy generation, including an analytical criterion development using Taylor series (Taylor Series Method) and a numerical criterion development based on the Monte Carlo Method. The virtual entropy generation is a versatile concept that can be used in not only in measurement error, but also in quantifying defects in models or materials, numerical residual errors, etc.