The thermal wizard is a set of java applets that contains an abundance of useful information and tools for anyone teaching or working in the thermal sciences. Unit converters, tables of material properties, and calculators for both heat transfer and head loss coefficients are among the items included.
The applets contained in the module can be used to simulate all three modes of heat transfer: conduction, convection and radiation. The conduction calculators can be used to calculate heat transfer and temperature gradients across a multilayer plate, embedded plates and cylinders, and across contacting surfaces. The convection calculator considers both free and forced convection from simple geometric shapes. The radiation calculator can be used to determine radiation heat transfer between two surfaces that are either parallel or perpendicular. The applet can also be used to calculate head losses for several simple duct elements.
To deomonstrate the relationships involved in many elementary problems of heat transfer and air flow.
To learn how to use the rate equations of conduction, convection and radiation to calculate heat transfer rates in systems of rectangular or cylindrical geometry.
To learn how to find the head losses in piping systems.
Target Student Population:
Undergraduate students in engineering taking a heat transfer course.
Prerequisite Knowledge or Skills:
Konowledge of the rate equations for the three modes of heat transfer and understanding of minor loss relations in piping systems.
Type of Material:
Java applet calculator
Can be used in an introductory heat trasnfer course.
Web browser that runs java applets.
Evaluation and Observation
The site provides:
1) A very useful collection of unit converters 2) A wide collection of material properties 3) An array of useful online calculators
The unit converters provide conversions for nearly 40 units ranging from acceleration to work. The user is free to select the units for both the original property and the final property, and 5-10 sets of units are available for each property.
Property tables are included for common metals, non-metals, gases, and liquids, with separate tables for air and water. Thermal conductivity, density, and specific heat values are included in all of the tables, and viscosity data are included in the gas and liquid tables.
Calculators offered include conduction calculators for heat transfer through multi-layer walls and cylinders, and heat transfer from several embedded objects such as plates and cylinders. Convection calculators include forced convection over plates and rods and natural convection from horizontal plates in different orientations. Radiation calculators include radiation between parallel and perpendicular rectangles and parallel circular surfaces. Finally head-loss calculators are included to determine losses from duct inlets and outlets and across screens and louvers.
Potential Effectiveness as a Teaching Tool
Can be used as a demonstrative tool for teaching fuindamentals of heat transfer. Each applet comes with an explanatory pop-up display of pertinent theory with a link for additional information. The applets can be used to augment lectures and to serve as tool for solving practice problems in class.
Each of the calculators offers the user a "Do You Want to Know More?" button which,
when clicked, brings up a full discussion of the topic at hand, including references. These discussions are excellent from a pedagogical perspective and make this site very effective as a teaching and learning tool.
Unlike the unit converters, the remaining portions of the site employ SI units exclusively. While not a major concern, it would be very useful if the user could select either SI or English units for the various calculators.
Ease of Use for Both Students and Faculty
The site is very easy to use by anyone at all familiar with online materials. The menu items and buttons are all laid out in a convenient and intuitive manner.
Other Issues and Comments:
Overall this is a very good calculator for learning how to calculate temperatures based on the geometic relations and rate equations for the modes of heat transfer. It is easy to use and for one to understand better the three modes of heat transfer.