# Heat Transfer Enhancement for Finned-Tube Heat Exchangers with Vortex Generators: Experimental and Numerical Results

## Abstract

A combined experimental and numerical investigation is under way to investigate heat transfer enhancement techniques that may be applicable to large-scale air-cooled condensers such as those used in geothermal power applications. The research is focused on whether air-side heat transfer can be improved through the use of finsurface vortex generators (winglets,) while maintaining low heat exchanger pressure drop. A transient heat transfer visualization and measurement technique has been employed in order to obtain detailed distributions of local heat transfer coefficients on model fin surfaces. Pressure drop measurements have also been acquired in a separate multiple-tube row apparatus. In addition, numerical modeling techniques have been developed to allow prediction of local and average heat transfer for these low-Reynolds-number flows with and without winglets. Representative experimental and numerical results presented in this paper reveal quantitative details of local fin-surface heat transfer in the vicinity of a circular tube with a single delta winglet pair downstream of the cylinder. The winglets were triangular (delta) with a 1:2 height/length aspect ratio and a height equal to 90% of the channel height. Overall mean fin-surface Nusselt-number results indicate a significant level of heat transfer enhancement (average enhancement ratio 35%) associated with the deployment of themore »

- Authors:

- Publication Date:

- Research Org.:
- Idaho National Laboratory (INL)

- Sponsoring Org.:
- USDOE

- OSTI Identifier:
- 910835

- Report Number(s):
- INEEL/CON-01-01491

TRN: US200802%%212

- DOE Contract Number:
- DE-AC07-99ID-13727

- Resource Type:
- Conference

- Resource Relation:
- Conference: 12th International Heat Transfer Conference,Grenoble, France,08/18/2002,08/22/2002

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 99 - GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; ASPECT RATIO; FORECASTING; HEAT EXCHANGERS; HEAT TRANSFER; NUSSELT NUMBER; PRESSURE DROP; REYNOLDS NUMBER; SIMULATION; TRANSIENTS; VELOCITY; finned-tube; heat exchangers; vortex generators

### Citation Formats

```
O'Brien, James Edward, Sohal, Manohar Singh, and Huff, George Albert.
```*Heat Transfer Enhancement for Finned-Tube Heat Exchangers with Vortex Generators: Experimental and Numerical Results*. United States: N. p., 2002.
Web.

```
O'Brien, James Edward, Sohal, Manohar Singh, & Huff, George Albert.
```*Heat Transfer Enhancement for Finned-Tube Heat Exchangers with Vortex Generators: Experimental and Numerical Results*. United States.

```
O'Brien, James Edward, Sohal, Manohar Singh, and Huff, George Albert. Thu .
"Heat Transfer Enhancement for Finned-Tube Heat Exchangers with Vortex Generators: Experimental and Numerical Results". United States. https://www.osti.gov/servlets/purl/910835.
```

```
@article{osti_910835,
```

title = {Heat Transfer Enhancement for Finned-Tube Heat Exchangers with Vortex Generators: Experimental and Numerical Results},

author = {O'Brien, James Edward and Sohal, Manohar Singh and Huff, George Albert},

abstractNote = {A combined experimental and numerical investigation is under way to investigate heat transfer enhancement techniques that may be applicable to large-scale air-cooled condensers such as those used in geothermal power applications. The research is focused on whether air-side heat transfer can be improved through the use of finsurface vortex generators (winglets,) while maintaining low heat exchanger pressure drop. A transient heat transfer visualization and measurement technique has been employed in order to obtain detailed distributions of local heat transfer coefficients on model fin surfaces. Pressure drop measurements have also been acquired in a separate multiple-tube row apparatus. In addition, numerical modeling techniques have been developed to allow prediction of local and average heat transfer for these low-Reynolds-number flows with and without winglets. Representative experimental and numerical results presented in this paper reveal quantitative details of local fin-surface heat transfer in the vicinity of a circular tube with a single delta winglet pair downstream of the cylinder. The winglets were triangular (delta) with a 1:2 height/length aspect ratio and a height equal to 90% of the channel height. Overall mean fin-surface Nusselt-number results indicate a significant level of heat transfer enhancement (average enhancement ratio 35%) associated with the deployment of the winglets with oval tubes. Pressure drop measurements have also been obtained for a variety of tube and winglet configurations using a single-channel flow apparatus that includes four tube rows in a staggered array. Comparisons of heat transfer and pressure drop results for the elliptical tube versus a circular tube with and without winglets are provided. Heat transfer and pressure-drop results have been obtained for flow Reynolds numbers based on channel height and mean flow velocity ranging from 700 to 6500.},

doi = {},

journal = {},

number = ,

volume = ,

place = {United States},

year = {Thu Aug 01 00:00:00 EDT 2002},

month = {Thu Aug 01 00:00:00 EDT 2002}

}