June 14, 2009
June 14, 2009
June 17, 2009
14.838.1 - 14.838.13
Learning about Blood through a Property Data Base Project
Introduction An understanding of the physical nature of blood is critical in a biomedical engineering program. For programs with a mechanical engineering orientation, knowing and understanding the thermophyscial properties of blood is essential in modeling the operations of such biomedical devices as artificial heart valves, blood pumps, left ventricular assist devices, and artificial hearts. To build this knowledge base with mechanical engineering students, a project was developed and implemented in a senior level elective course in thermal design. The project involved the students building an Excel spreadsheet calculator for blood properties. With the user specifying blood hematocrit, temperature, and pressure, the spreadsheet will calculate values for 13 different thermophysical properties, which include thermodynamic properties such as enthalpy and entropy and transport properties such as thermal conductivity and kinematic viscosity.
Since little data exists in the form needed for the project, a portion of this paper will focus on the constitutive equations that were developed by the authors for the project. The models used in the development of functional forms of the properties dependent on hematocrit, temperature, and pressure are explored. The paper provides the details of the project assignments, including lecture material. Student feedback on this project was collected and will be shared in the paper.
Project Description The blood project serves as the first of 5 projects in a senior level thermal design course. When a biomedical theme is used in the course, subsequent projects use the blood property data base developed for the modeling of cardiopulmonary bypass systems and hemodialysis machines. The course in which this project is used has an extensive set of course learning objectives. Those that are pertinent to the blood project are provided below.
Students are able to determine thermodynamic properties using mathematical models Students are able to represent design data in terms of curve fits Students are able to develop a computerized property data base Students are be able to program in Excel Students are able to graph in Excel
For the blood project the student is asked to develop an Excel spreadsheet that will allow the calculation of a number of human blood properties at specified hematocrit (over a range from 0 to 0.60), temperature (over a range from 280 K to 330 K), and pressure (over a range from 80 kPa to 150 kPa). The set of thermodynamic properties to be calculated include yield stress, specific volume, density, specific heat, internal energy, enthalpy, entropy, and the thermal expansion coefficient. For the thermodynamic properties constitutive equations are provided to the students (shown in Figure 1). The students are directed to use the symbolic manipulator associated with MATLAB to evaluate thermodynamic properties that require integration or differentiation. The
Somerton, C. (2009, June), Learning About Blood Through A Property Database Project Paper presented at 2009 Annual Conference & Exposition, Austin, Texas. https://peer.asee.org/4774
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