Comprehensive Guide to Mechanical Device Properties

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Discussion Overview

The discussion revolves around the properties of various mechanical devices such as steam turbines, pumps, nozzles, diffusers, throttles, condensers, and heat exchangers. Participants explore the complexities of these devices, including their operational equations and the specific conditions affecting their performance.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant requests a comprehensive resource detailing the properties and equations related to various mechanical devices, including specific conditions like inlet and exit states, mass flow, and efficiencies.
  • Another participant suggests that the information is specific to each piece of equipment and recommends consulting manufacturer catalogs or selection software for accurate data.
  • A third participant questions whether the inquiry pertains to the properties of the devices themselves or the substances used within them, noting that enthalpy and entropy are properties of substances.
  • Another participant emphasizes the complexity of the devices, stating that ideal equations depend on various operational modes (e.g., gas vs. liquid, boiling conditions, presence of solids) and suggests focusing on a specific case for clarity.
  • This participant also mentions that the efficiency of pumps and engines should be sourced from manufacturers and refers to extensive resources like "Perry's Handbook" for further information.

Areas of Agreement / Disagreement

Participants express differing views on the nature of the requested information, with some emphasizing the need for specificity and others highlighting the complexity and variability of the devices' properties. No consensus is reached regarding a singular approach or resource.

Contextual Notes

The discussion reflects limitations in generalizing properties across different devices due to varying operational conditions and the dependence on manufacturer-specific data. There is also an acknowledgment of the extensive nature of available resources.

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I am looking for a table or resource of any kind that can break down properties for me for different devices such as Steam Turbines, Pumps, Nozzles, Diffusers, Throttle, Condenser, Heat Exchanger, etc.

Basically like for a pump it would be

1inlet
1exit

Mi=Me(constant mass flow)

de/dt = q - w + sum(Mi)(u) - sum(Me)(u)
which would show that w = hi-he

then

dS/dt = 0+0+0+Mi(si)-Me(se) +0 (reversible process)

Si = Se

inlet state is compressed liquid, exit state is compressed liquid, typical efficiencies for a pump.

like that kind of thing...trying to get a complition cause I am working with this book and its confusing and everything is all over the place :(
 
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This information is specific to the particular piece of equipment. You'd have to look at a manufacturer's catalog or use selection software.
 


Are you looking for properties of the 'devices'? Or of the substances that will be used in the devices? Enthalpy and entropy are properties of substances and not devices as far as I know. But, maybe I am mistaken.

Casey
 


What you want is to learn chemical process engineering in 1 simple step. I'm afraid that it's not all that simple...

(Almost) all of these devices have "ideal situation" equations... but those almost all again depend on the mode of operation (are you having a gas, liquid?... is it boiling?... is it turbulent?... any solids present (in suspension) perhaps?)

Power of a (liquid) pump: P = g*flow*dh
Power of a gas pump is different... and I'm not in the mood to explain. Anyway, it's not even called a pump... it's a compressor.
The efficiency of the pump (and of the engine powering it) is indeed something that you must ask a manufacturer.

It would really help a lot if you are a lot more specific, so we can focus on just one case and explain that. Now you are asking us to explain you all there is. And all I could do is refer to something massive as "Perry's Handbook". It is definitely "a table or resource", but in fact, it's well over 3000 pages of it... :-p
 

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