Thermofluids Week 5 quiz.

Question 1

What Is specific gravity?

Answer 1

The ratio of a substance’s density to the density of a reference substance. Dimensionless quantity. E.g. average density of substance / density of water. If less than 1 then substance will float. If greater than 1 substance will no float as the substance is more dense on average than water.

Question 2

What is the specific volume?

Answer 2

The volume occupied/space occupied by a unit of mass (1kg of mass.)
Reciprocal of density.

Question 3

What is the most crucial factor when scaling?

Answer 3

You must make sure that the dimensionless quantities are the same in the model and prototype. If the model cannot be made using the same fluid as the prototype without compromising the Reynolds or Froude numbers then the fluid should be changed in order to ensure accurate geometric scaling.

Question 4

What is the difference between model and a prototype?

Answer 4

A model is a small-scale object which we use to run tests on to observe it’s behaviour. A prototype is a full-size object which is akin to the real thing however is not built fro production and is just built for full-size testing.