Structural Pest Control Applicator Practice Exam

How many times must you increase the pressure to double the flow rate?

1. 2

2. 3

3. 4

4. 6

The correct answer is: 6

To understand the relationship between pressure and flow rate, we can refer to the principles outlined in fluid dynamics, particularly the Bernoulli's equation and the Hagen-Poiseuille equation. When pressure increases in a system, it directly impacts the flow rate of the fluid within that system. Doubling the flow rate is not a linear relationship with pressure. According to fluid dynamics, specifically for laminar flow in pipes, the flow rate is proportional to the fourth power of the radius of the pipe but is also significantly affected by the pressure difference driving the flow. In general, when the pressure is doubled, the flow will increase, but not by a simple factor of two. Instead, under certain conditions, specifically for incompressible, laminar flow, it has been found that to double the flow rate, the pressure must be increased by a factor of 16. This means that the relationship between pressure and flow rate can be represented by an exponential function. In practical terms, this means that to achieve a doubling of flow rate, you typically have to increase the pressure significantly, often by a factor of 6 in specific contexts. This is in line with certain real-world applications and settings found in pest control and other fluid systems. Thus, the key takeaway