The main reason for increasing heat transfer coefficient in the entrance region?

More Taha Ahmed Abdullah's questions See All

To improve heat transfer by adding ribs, where is the best location for fixing ribs in the entrance region or fully developed, why?

improve by adding ribs

05 June 2019 3,990 1 View

Why the convection heat transfer increase with adding nano fluid particles to the water flowing in pipe?

Nano fluid concentration

05 June 2019 6,837 1 View

How we can increase Nusselt number at forced convection heat transfer?

Increasing Nusselt number.

03 April 2019 1,412 7 View

What can i do to appear the citation of my article in the research gate?

I have citation to my article but not exsist in the research gate.

01 February 2019 1,851 16 View

How can i convert results in FORTRAN from notepad to excel file?

how can i convert results in FORTRAN from notepad to excel file

11 December 2018 609 6 View

New Journal, "Integrative Psychological and Behavioral Science" -- do you not know, and have you not seen, this done before?

Question to you and THEM, the New Journal, "Integrative Psychological and Behavioral Science" -- do you not know, and have you not seen, this done before? There appears to be a core problem for...

02 March 2021 3,024 2 View

What are the countries most affected by extreme rainfall as a result of climate change?

Increased heat, drought and insect outbreaks, all associated to climate change, have increased wildfires. Decreasing water supplies, declined agricultural yields, health impacts in cities owing to...

01 March 2021 7,168 9 View

Does any one can help me choose a reasonable basis set for intermediate metal ions interactions with guanine (i.e Fe2+, Mn2+, Cu2+ and exc.)?

Hello every body Does any one has any idea to help me choose a reasonable basis set for intermediate metal ions (i.e Fe2+, Mn2+, Cu2+ and exc.) interactions with guanine or other DNA organic...

01 March 2021 6,187 2 View

What is recommended for solid domain in ANSYS FLUENT?

Should I mesh the solid domain ? or should I use wall thickness? or Shell conduction? for Heat Transfer between two fluids of a Heat Exchanger. what is recommended?

01 March 2021 9,785 3 View

Heat exchanger with liquid Nitrogen as coolant?

I want to cool Natural Gas from 195 Kelvin to 138 Klevin in a heat exchanger by using liquid nitrogen as the coolant medium. When entering the heat exchanger, the liquid nitrogen will have a...

01 March 2021 6,450 5 View

How can i resolve the "final solutuin is not converged" error in Comsol for my heat transfer simulation??

I have been trying to simulate heat transfer problem in Comsol 5.5 for long time but it always throw an error stating: "Failed to find a solution. Maximum number of Newton iterations...

28 February 2021 8,626 3 View

What could be some reasons why unstimulated monocytes are getting activated?

Im doing PBMC isolation -> CD14+ enrichment using magnetic beads -> stimulation setup. My negative control is just cells in cRPMI but they seem to get activated over and over again.

28 February 2021 7,883 3 View

PUC19 as a transfer plasmid for lentiviral delivery?

Hello, Is it possible to use pUC19 as a transfer vector to be packed in using the second generation viral particles packaging system( pMD2.G; psPAX2 plasmids)? As far as I understand it there is...

28 February 2021 4,868 2 View

Why does intensity drops as concentration increases?

Is there any reason for decrease in fluorescence emission intensity of HSA,BSA when increase the concentration ?

28 February 2021 3,653 4 View

POlymer+DMSO solution and moisture??

What could be the reason of moisture at the sides of Vial when I am preparing my polmyer+DMSO solution for membrane fabrication? What etiquettes I am possibly missing here?

28 February 2021 6,516 5 View

Mojtaba Bezaatpour

From the following equation, it is clear that the highest local heat transfer coefficient occurs at the entrance, where the temperature difference between the fluid and the surface is maximum.

h=q''/(Ts-Tb) ; Tb=balk temp Ts=surface temp

However, it decreases with the distance from entrance as the fluid temperature becomes closer to the surface temperature and temperature difference decreases.

Another justification can be boundary layer thickness. Boundary layers are thinner at the entrance and result in higher local heat transfer coefficient.

Best regards.