Development of heat transfer method for non-intrusive pressure measurement in natural gas pipelines
- Battelle, Columbus, OH (United States)
- Columbia Gas of Ohio, Columbus, OH (United States)
A method for non-intrusive measurement of internal pressures in flowing and non-flowing natural gas distribution pipelines has been developed. The method is based on temperature changes observed at various locations on the outside wall of the pipe in response to a circumferential band of heat applied to it. Because of the complex flow patterns in the pipe, the pressure-related phenomena induce second-order effects on the heat transfer to the gas or liquid in the pipeline. Experimental results from both laboratory and field measurements have been compared with predictions from TEMPEST, a computation fluid dynamics (CFD) model, to aid in understanding the flow characteristics. In this method, a 2.5-in. band or ring heater device placed around the outer circumference of the pipe is used to apply that to the outer wall of the pipe. The effect of heat input ranging from 250 to 1,000 watts has been evaluated for pipe diameters ranging from 4 in. to 12 in. The expected range of Reynolds numbers spans the laminar, transitional, and turbulent flow regimes, thus adding significant complexity to the problem. Results have shown that a heater power of about 1,000 watts for flowing gas and 250 watts for non-flowing gas enables an acceptable estimate of pressures for most cases. The method can be used to effectively determine whether a pipe is filled with gas or liquid. It can also indicate whether the gas is flowing or static. For flowing gas, upstream-to-downstream and top-to-bottom temperature differences at the surface of the pipe are jointly used to determine gas flow rate and pressure. For no-flow conditions, the upstream-to-downstream temperature difference is zero, and pressures ranging from 0 to 150 psig can be differentiated solely by the temperatures along the outside wall of the pipe.
- OSTI ID:
- 110042
- Report Number(s):
- CONF-940659--; ISBN 0-7918-1369-X
- Country of Publication:
- United States
- Language:
- English
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