gas flow rate in heat exchanger

[dgau008]

hi, i am doing an project on heat exchangers. i need to find the flow rate of gas and pressure drop in heat exchanger. this heat exchanger is using in fireplace where hot gas coming out of place and cooler getting in the fire place. somebody please suggest me right way to measure these two parameters. i tried pitete tube and anemometre but both are not accurate...........

 

[vpl]

Why don't you believe they are accurate? I've seen both used before.

Patricia Lougheed

******

Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of the Eng-Tips Forums.

 

[dgau008]

vpl (Nuclear)

it varies each and every time, i am not sure whether this is right method. as earlier i used to do like this way. this time i think flowing gases are combusted or burnt hot gases may be it changes the results.........
what do you think regarding this

 

[davefitz]

dgau008:

I am not sure of your configuration, but if you are measuring the flow of combusted gases out of a traditional fireplace that exhausts thru a chimney using " natural draft" bouyancy effect, then the gas flow will vary based on wind flowrates across the chimney exit plane and also based on the rate of fuel burning in the firebox. Both of these effects are random or chaotic and cannot be predicted.

You would be better by measuring the flowrate and temperature change across the side of the HX that is using a controlled flowate of gases that are being driven by a fan.