contestada

0.7-kg of r-134a is expanded isentropically from 800 kpa and 50°c to 140 kpa. determine the total heat transfer and work production for this expansion.

Respuesta :

There will be no heat transmission, and the system's work is 25.27 Kj.

The calculation for total heat transfer and work production:

Provided,

The mass of r-134a = 0.7 kg

Initial pressure of the system, P₁ = 800 kpa

Initial temperature of r-134a, T₁ = 50°C = 273+ 50 = 323 K

Final pressure of the system, P₂ = 140 kpa

From the superheated refrigerant r-134a

P₁ = 800 kpa & T₁ = 50°C

the internal energy, u₁ = 263.87 Kj/kg &

the entropy, s₁ = 0.9803 Kj/kg .K

There won't be any heat transmission because the process is isentropic.

So, Q = 0 KJ

Due to the isentropic nature of the operation, the ultimate entropy is determined by

s₂ = s₁ = 0.9803 Kj/kg .K

From the r-134a superheated refrigerant

at P₂ = 140 kpa & entropy s₂ = 0.9803 Kj/kg .K

the internal energy,u₂ = 227.77 K/kg

The work on the system is provided by

W = m x (u₂-u₁)

W = 0.7 x(227.77 - 263.87)

W = 0.7 x (-36.1)

W = -25.27 KJ

A negative number means the system is doing the task.

As a result, there won't be any heat transfer, and the system will only have used 25.27 KJ of energy.

Learn more about the work here:

https://brainly.com/question/20309171

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