Question

What would happen if we attempted to decelerate a supersonic fluid with a diverging diffuser?

Short answer

Answer: When a supersonic fluid flows through a diverging diffuser, it undergoes a shock wave due to the geometry of the channel and the nature of supersonic flow. This shock wave causes a sudden deceleration of the flow, an increase in pressure and density, and a loss of kinetic energy.

Step-by-step solution

Understand the problem

To solve this exercise, we need to have a clear understanding of the behavior of supersonic fluids and how they react when flowing through different types of channels, such as converging or diverging diffusers.

Understand the concept of supersonic flow

Supersonic flow is when the fluid velocity is higher than the speed of sound in that fluid. In this case, the fluid is moving faster than the pressure waves (sound waves) it generates.

Recall the behavior of supersonic flows in converging and diverging channels

In the case of supersonic flows, they behave opposite to subsonic flows when encountering converging or diverging channels. When a supersonic flow encounters a converging channel, its velocity increases, and pressure and density decrease. On the other hand, when it encounters a diverging channel, its velocity decreases, and pressure and density increase.

Describe the effect of decelerating a supersonic fluid in a diverging diffuser

When attempting to decelerate a supersonic fluid in a diverging diffuser, the fluid velocity will decrease, and pressure and density will increase due to the geometry of the channel. However, the flow cannot be slowed down to subsonic speeds smoothly in a simple diverging diffuser without a shock wave occurring.

Introduce the concept of shock waves

Shock waves are abrupt changes in pressure, density, and velocity that occur when a supersonic fluid decelerates to subsonic speeds. In the scenario of a supersonic fluid in a diverging diffuser, the fluid will undergo a shock wave, which will lead to a sudden deceleration, an increase in pressure and density, and a loss of kinetic energy.

Conclusion

When attempting to decelerate a supersonic fluid in a diverging diffuser, the fluid will undergo a shock wave due to the geometry of the channel and the nature of supersonic flow. The shock wave causes a sudden deceleration of the flow, increased pressure and density, and loss of kinetic energy.