Labrynth Seal Design - Calculating Pressure Drop

1- Δp[ N/m^2^]= ρ*(v/α)^2/2 with ρ- specific mass [kg/m^3];v [m/s];α= flow coefficient ≈0.6

2- Equation valid for under critical conditions

If total pressure drop is known then the number of steps has to be so that the maximal pressure drop on a step stays still under the critical limit.

Volume between two labyrinths should be big enough to allow expansion.

It is better due to expansions to work in mass flow which is a constant, the specific volume will vary a lot from step to step.

If other questions please ask

Dear Sir can you plz tell me from where have you qouted this formulla i mean if i could get the author name and title of the book then it would be more helpful for me.

thanks,

Dear Guest,

It is not the scope of CR4 participants to make the research work for the OP.

In most cases the OP asks for help AFTER he found a solution or an information and he/she is not sure either about contend or about results.

In your case I gave you a way to work on but if you want more you have to LEARN by your self.

The question in your second request shows that, unfortunately, your knowledge is too low as per today to understand how a labyrinth seal works.

I dare say that you should ask for help from a more qualified person since the solution is NOT an equation but first of all the understanding of the problem you are confronted with.

The equation I wrote is the most basic equation of a fluid flow and you are not aware of it and what it means.

I stop here and when you made a progress you are free to ask for support.

May be some other CR4 participant will be willing to transgress the CR4 rules do your work, I am not.

If you would have made the slightest effort to search with an engine informations about labyrinths you would have noticed the large amount available for your usage but as mentioned above I doubt very much you will be able to use it the right way and for the benefit of the project. Sorry!

Dear friend

In spite of confirming "nick name"_to continue the discussion;you can find the origin of formula in every text of fluid mechanics ex. "fluid mechanics by streeter OR fox and so on" in chapters related to friction loss calculation under the title of (for instance)Minor loss in fluid flows.Of course you need to do some manipulation for creating a relation between simple minor friction loss and seal blades.

good luck

I do not know how far you are informed about labyrinths but there is no manipulation to be done between "minor" friction losses and seal blades for different reasons : 1- those losses are not friction losses but due to the flow itself 2- they are not minor but in fact major. You are right in every book about fluid mechanics the equation is present.

My reaction which could appear as rough has a reason. During last months the number of OP who do NOT do any trial to find by themselves a solution and ask for what they could find by simply "google" a question to their problem grows exponentially! They do not consider CR4 as a helping hand but as a way to avoid own work. The consequence is that the level of CR4 is going down. Several participants with a higher level are not any more present because of it.

A few days ago I recommended to an OP to look at the catalogue of a bearing manufacturer for the answer he wanted to have. I got a "off-topic" NGA although m recommendation was correct since if he looks in a catalogue he can get the BEST information. I consider that the "good will" of many participants is in fact NOT a help for the personal evolution of OPs.

From the other point of view when a higher level question appears the number of answers is very low. This is a sign about mean level of interest an available knowledge. Look a t the questions with the higher number of participants or with the higher number of persons looking at. Statistics reveal some aspects.

Dear nick name

I've been working in a power plant for years. Although I've seen a big various seals, among them Labyrinth Seal, and dealed with them, but "I confess at the court, I am not a designer!" Then every thing I know about this kind of seal is due to either experience or personal studies with my own analysis.

"Friction loss" is merely an idiom that we applied to pressure loss in some (for example) piping parts in usual technical talking not in a special technical court where every word has special meaning which should be applied cautiously.

Flow of a fluid through the blades of seal in my opinion can be something like passing of fluid through several stages of orifice somehow. Of course there is a fan after the final stage of labyrinth seal to suction and even creating a negative pressure in some cases.(there's no need to speak about it here)

Then whatever caused to use "minor loss" was likening labyrinth stages to orifice stages. And you know pressure loss is called "minor loss" for some things like orifices, valves and fittings in texts of fluid mechanics.

I agree with you in most of your other opinions about questions and sort of things.

And last things: I think like you about "the correct way of searching, working out and finding" and always have tried to be so. Then hopefully continue this technical internet relation through CR4.

Losses in a pipes (l/d>>1) are friction losses, losses in an orifice are local losses which are less related to friction and more to the flow acceleration (+ or -) function of the flow section area changes. Of course in every loss there is also a part of friction but it is in the case of "local losses" not the major part.

If the OP has the slightest notion about fluid dynamics what I wrote as hints would be sufficient for him/her to solve the problem but with a small personal effort. This effort is not wished by the -unfortunately- great majority of OP-s. What they want is "an equation" they do not want to think only to crush numbers, no intellectual effort.

Dear nick name

I've been working in a power plant for years. Although I've seen a big various seals, among them Labyrinth Seal, and dealed with them, but "I confess at the court, I am not a designer!" Then every thing I know about this kind of seal is due to either experience or personal studies with my own analysis.

"Friction loss" is merely an idiom that we applied to pressure loss in some (for example) piping parts in usual technical talking not in a special technical court where every word has special meaning which should be applied cautiously.

Flow of a fluid through the blades of seal in my opinion can be something like passing of fluid through several stages of orifice somehow. Of course there is a fan after the final stage of labyrinth seal to suction and even creating a negative pressure in some cases.(there's no need to speak about it here)

Then whatever caused to use "minor loss" was likening labyrinth stages to orifice stages. And you know pressure loss is called "minor loss" for some things like orifices, valves and fittings in texts of fluid mechanics.

I agree with you in most of your other opinions about questions and sort of things.

And last things: I think like you about "the correct way of searching, working out and finding" and always have tried to be so. Then hopefully continue this technical internet relation through CR4.

Dear nick name

I've been working in a power plant for years. Although I've seen a big various seals, among them Labyrinth Seal, and dealed with them, but "I confess at the court, I am not a designer!" Then every thing I know about this kind of seal is due to either experience or personal studies with my own analysis.

"Friction loss" is merely an idiom that we applied to pressure loss in some (for example) piping parts in usual technical talking not in a special technical court where every word has special meaning which should be applied cautiously.

Flow of a fluid through the blades of seal in my opinion can be something like passing of fluid through several stages of orifice somehow. Of course there is a fan after the final stage of labyrinth seal to suction and even creating a negative pressure in some cases.(there's no need to speak about it here)

Then whatever caused to use "minor loss" was likening labyrinth stages to orifice stages. And you know pressure loss is called "minor loss" for some things like orifices, valves and fittings in texts of fluid mechanics.

I agree with you in most of your other opinions about questions and sort of things.

And last things: I think like you about "the correct way of searching, working out and finding" and always have tried to be so. Then hopefully continue this technical internet relation through CR4.

Dear nick name

I've been working in a power plant for years. Although I've seen a big various seals, among them Labyrinth Seal, and dealed with them, but "I confess at the court, I am not a designer!" Then every thing I know about this kind of seal is due to either experience or personal studies with my own analysis.

"Friction loss" is merely an idiom that we applied to pressure loss in some (for example) piping parts in usual technical talking not in a special technical court where every word has special meaning which should be applied cautiously.

Flow of a fluid through the blades of seal in my opinion can be something like passing of fluid through several stages of orifice somehow. Of course there is a fan after the final stage of labyrinth seal to suction and even creating a negative pressure in some cases.(there's no need to speak about it here)

Then whatever caused to use "minor loss" was likening labyrinth stages to orifice stages. And you know pressure loss is called "minor loss" for some things like orifices, valves and fittings in texts of fluid mechanics.

I agree with you in most of your other opinions about questions and sort of things.

And last things: I think like you about "the correct way of searching, working out and finding" and always have tried to be so. Then hopefully continue this technical internet relation through CR4.