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ibell / coolprop

Deprecated version - go to
https://github.com/CoolProp/CoolProp
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viscosity for isopentane and pentane are incorrect #269

Open krule012 opened 6 years ago

krule012 commented 6 years ago

The calculated viscosity in coolprop for both isopentane and n-pentane seems incorrect (specifically below 200 K). I would expect the gradient in viscosity to be larger for both pure fluids below 200 K. I don't have another data source that I can compare this to. Could you verify against pure fluid properties from NIST?

ibell commented 6 years ago

First off, this is deprecated repository for CoolProp; issues should be sent here: https://github.com/coolprop/coolprop/issues

Where is your data? :) CoolProp implements the models listed on each of the info pages: http://www.coolprop.org/fluid_properties/fluids/n-Pentane.html#fluid-n-pentane and ECS with these parameters for isopentane: http://www.coolprop.org/fluid_properties/fluids/Isopentane.html#fluid-isopentane . Feel free to provide a better model, but I do not believe than any exists.

On Fri, Aug 25, 2017 at 9:56 AM, krule012 notifications@github.com wrote:

The calculated viscosity in coolprop for both isopentane and n-pentane seems incorrect (specifically below 200 K). I would expect the viscosity for isopentane to be greater than n-pentane at temperatures below 200 K. I would also expect the gradient in viscosity to be larger for both pure fluids below 200 K.

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krule012 commented 6 years ago

Ian,

I observed a discrepancy between the calculated viscosity curve from coolprop as compared with refprop. Unfortunately I am unable to provide a better source for this calculation. Do you have a license for Refprop that you could use to run a comparison?

I've been using coolprop extensively, no better free source for thermophysical fluid properties exists (so far as I know). Thank you for all of your contributions!

On Aug 27, 2017 1:05 PM, "Ian Bell" notifications@github.com wrote:

First off, this is deprecated repository for CoolProp; issues should be sent here: https://github.com/coolprop/coolprop/issues

Where is your data? :) CoolProp implements the models listed on each of the info pages: http://www.coolprop.org/fluid_properties/fluids/n-Pentane. html#fluid-n-pentane and ECS with these parameters for isopentane: http://www.coolprop.org/fluid_properties/fluids/Isopentane. html#fluid-isopentane . Feel free to provide a better model, but I do not believe than any exists.

On Fri, Aug 25, 2017 at 9:56 AM, krule012 notifications@github.com wrote:

The calculated viscosity in coolprop for both isopentane and n-pentane seems incorrect (specifically below 200 K). I would expect the viscosity for isopentane to be greater than n-pentane at temperatures below 200 K. I would also expect the gradient in viscosity to be larger for both pure fluids below 200 K.

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ibell commented 6 years ago

Actually, I am now a developer of REFPROP. Do you know what models are used in REFPROP for these two fluids?

On Sun, Aug 27, 2017 at 4:00 PM, krule012 notifications@github.com wrote:

Ian,

I observed a discrepancy between the calculated viscosity curve from coolprop as compared with refprop. Unfortunately I am unable to provide a better source for this calculation. Do you have a license for Refprop that you could use to run a comparison?

I've been using coolprop extensively, no better free source for thermophysical fluid properties exists (so far as I know). Thank you for all of your contributions!

On Aug 27, 2017 1:05 PM, "Ian Bell" notifications@github.com wrote:

First off, this is deprecated repository for CoolProp; issues should be sent here: https://github.com/coolprop/coolprop/issues

Where is your data? :) CoolProp implements the models listed on each of the info pages: http://www.coolprop.org/fluid_properties/fluids/n-Pentane. html#fluid-n-pentane and ECS with these parameters for isopentane: http://www.coolprop.org/fluid_properties/fluids/Isopentane. html#fluid-isopentane . Feel free to provide a better model, but I do not believe than any exists.

On Fri, Aug 25, 2017 at 9:56 AM, krule012 notifications@github.com wrote:

The calculated viscosity in coolprop for both isopentane and n-pentane seems incorrect (specifically below 200 K). I would expect the viscosity for isopentane to be greater than n-pentane at temperatures below 200 K. I would also expect the gradient in viscosity to be larger for both pure fluids below 200 K.

— You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub https://github.com/ibell/coolprop/issues/269, or mute the thread https://github.com/notifications/unsubscribe-auth/ABxha5Cr8FbHAsyNxuAs- GogSiyD4jdPks5sbu7DgaJpZM4PC2Zu .

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krule012 commented 6 years ago

Based on the nature of your response, I would guess the same as Coolprop... The curves I had referenced from Refprop we're from an older version (I think v8 or v9). I had generated these back during my graduate research work. I'll go ahead and update my model using the curves from coolprop then.

Hopefully I didn't waste too much of your time.

I'll make sure to post any future issues at the link you provided below. The help link I had used was from the "v4 documents" website.

On Aug 27, 2017 5:08 PM, "Ian Bell" notifications@github.com wrote:

Actually, I am now a developer of REFPROP. Do you know what models are used in REFPROP for these two fluids?

On Sun, Aug 27, 2017 at 4:00 PM, krule012 notifications@github.com wrote:

Ian,

I observed a discrepancy between the calculated viscosity curve from coolprop as compared with refprop. Unfortunately I am unable to provide a better source for this calculation. Do you have a license for Refprop that you could use to run a comparison?

I've been using coolprop extensively, no better free source for thermophysical fluid properties exists (so far as I know). Thank you for all of your contributions!

On Aug 27, 2017 1:05 PM, "Ian Bell" notifications@github.com wrote:

First off, this is deprecated repository for CoolProp; issues should be sent here: https://github.com/coolprop/coolprop/issues

Where is your data? :) CoolProp implements the models listed on each of the info pages: http://www.coolprop.org/fluid_properties/fluids/n-Pentane. html#fluid-n-pentane and ECS with these parameters for isopentane: http://www.coolprop.org/fluid_properties/fluids/Isopentane. html#fluid-isopentane . Feel free to provide a better model, but I do not believe than any exists.

On Fri, Aug 25, 2017 at 9:56 AM, krule012 notifications@github.com wrote:

The calculated viscosity in coolprop for both isopentane and n-pentane seems incorrect (specifically below 200 K). I would expect the viscosity for isopentane to be greater than n-pentane at temperatures below 200 K. I would also expect the gradient in viscosity to be larger for both pure fluids below 200 K.

— You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub https://github.com/ibell/coolprop/issues/269, or mute the thread https://github.com/notifications/unsubscribe-auth/ABxha5Cr8FbHAsyNxuAs- GogSiyD4jdPks5sbu7DgaJpZM4PC2Zu .

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Reply to this email directly, view it on GitHub https://github.com/ibell/coolprop/issues/269#issuecomment-325227584, or mute the thread https://github.com/notifications/unsubscribe-auth/ ABxha7jbSuUYBNshuWFsGigmkGgm4GaVks5scebhgaJpZM4PC2Zu

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thorade commented 6 years ago

replaced by https://github.com/CoolProp/CoolProp/issues/1541 please close this issue here