#
**20) **In which of the following compressors, the flow of air through the compressor is parallel to its axis?

**Answer is:**

## Axial flow compressor

**Related KPCL AE Mechanical Question Papers - 2015 with Answer Key**

**Answer is:**

### Bootstrap system

**Answer is:**

### It measures the ratio of heat transferred into a fluid to the thermal capacity of the fluid.

**Answer is:**

### Reynolds number

**Explanation:**

The important dimensionless numbers in fluid mechanics are

1. Reynold’s number

2. Froude’s number

3. Weber’s number

4. Euler’s number

5. Mach’s number or Cauchy’s number

**Reynold’s number**: Reynold’s number is the ratio of inertia force to the viscous force.

**Froude’s number**: Froude’s number is the ratio of inertia force to the gravity force.

**Weber’s number**: Weber’s number is the ratio of inertia force to the surface tension force.

**Euler’s number**: Euler’s number is the ratio of inertia force to the pressure force.

**Mach’s number or Cauchy’s number**: Mach’s number or Cauchy’s number is the ratio of inertia force to the elastic force.