Does Watt's Law apply to flowing water in a pipe?

In summary, the heat generated by flowing water in a pipe is proportional to the product of the flow rate and pressure drop, similar to an electrical circuit. The units to obtain an answer in watts would be amperes for flow rate and volts for pressure drop.
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Jack of some trades
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Is the heat generated by flowing water in a pipe proportional to the product of the rate of flow and the pressure drop across the section of pipe in question, analogous to an electrical circuit? If so, what units would you plug into get an answer in watts?
 
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If the flow is at steady state and the pipe is insulated, then then change in specific enthalpy of the water is zero. So, $$C_p\Delta T+v(1-\alpha \bar{T})\Delta P=0$$where ##\alpha## is the volumetric coefficient of thermal expansion, ##C_p## is the specific heat capacity, v is the specific volume of the water and ##\bar{T}## in the second term is the average temperature in the pipe (that doesn't change much). So, the change in temperature from inlet to outlet is $$\Delta T=\frac{v(1-\alpha \bar{T})(-\Delta P)}{C_p}$$
If you imagine that the "heat generated" is ##\dot{m}C_p\Delta T## where ##\dot{m}## is the mass flow rate, then$$\dot{m}C_p\Delta T=\dot{m}v(1-\alpha \bar{T})(-\Delta P)=(1-\alpha \bar{T})\dot{V}(-\Delta P)$$,where ##\dot{V}## is the volumetric flow rate.
 
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Jack of some trades said:
Summary:: Is the heat generated by flowing water in a pipe proportional to the product of the rate of flow and the pressure drop?

Is the heat generated by flowing water in a pipe proportional to the product of the rate of flow and the pressure drop across the section of pipe in question, analogous to an electrical circuit? If so, what units would you plug into get an answer in watts?
This seems to be a correct statement (we do not want to confuse Temperature with Heat). With the electrical analogue I think the flow rate would be Amperes and the pressure drop Volts.
 

FAQ: Does Watt's Law apply to flowing water in a pipe?

Does Watt's Law apply to flowing water in a pipe?

Yes, Watt's Law applies to flowing water in a pipe. This law states that power (P) is equal to the product of voltage (V) and current (I), or P = VI. In the context of flowing water in a pipe, voltage can be thought of as the pressure, current can be thought of as the flow rate, and power can be thought of as the rate of energy transfer.

How is Watt's Law used in the context of flowing water in a pipe?

Watt's Law can be used to calculate the power (P) of the water flowing through a pipe by multiplying the pressure (V) by the flow rate (I). This can be useful in determining the efficiency of a water system or in designing a system to meet specific power requirements.

Is there a limit to the amount of power that can be generated from flowing water in a pipe using Watt's Law?

Yes, there is a limit to the amount of power that can be generated from flowing water in a pipe using Watt's Law. This limit is determined by the maximum pressure and flow rate that the pipe can handle without bursting. Additionally, the efficiency of the system and any external factors, such as friction or turbulence, can also affect the amount of power that can be generated.

Can Watt's Law be applied to all types of pipes and water systems?

Yes, Watt's Law can be applied to all types of pipes and water systems. However, it is important to consider the specific characteristics and limitations of each system when using this law. For example, the type and size of the pipe, as well as the properties of the water, can affect the accuracy of the calculations.

Are there any other laws or principles that should be considered when studying the power of flowing water in a pipe?

Yes, there are other laws and principles that should be considered when studying the power of flowing water in a pipe. For example, Bernoulli's principle, which states that the pressure of a fluid decreases as its speed increases, can also play a role in the power generation of flowing water in a pipe. Additionally, the laws of thermodynamics and fluid dynamics may also be relevant in certain situations.

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