## Steam Flow Analysis for PB do Brasil Ltda

This study is a computational analysis of a pipeline flow. The goal is the study of the flow pattern at the front of the flowmeter Deltaflow DF25 (Systec). The computational model extends from upstream the eccentric reducer to the front end of the flow meter.

## Problem Definition

1. Flow 270 tons/hour

- Inlet velocity u = 41.30 m/s
- Inlet temperature T = 510 Celsius
- Inlet pressure p = 111.8 bar
- Inlet density = 34.48 kg/m³ (linear interpolation from steam tables at 500 C)
- Inlet Reynolds number = 35,600 (based on pipe diameter d = 0.259 m)
- Flow dynamic viscosity 3. 10^{-5} N m/s
- Flow fully turbulent

2. Flow 340 tons/hour

- Inlet velocity u = 52.00 m/s
- Inlet temperature T = 510 Celsius
- Inlet pressure p = 111.8 bar
- Inlet density = 34.48 kg/m³ (linear interpolation from steam tables at 500 C)
- Inlet Reynolds number = 44,900 (based on pipe diameter d = 0.259 m)
- Flow dynamic viscosity 3. 10^{-5} N m/s
- Flow fully turbulent
## Modelling

- Eccentric Reducer 16″/12″ (ANSI 816.9-1978), with cosine variation of diameter
- Pipeline section upstream reducer to 12″ line (normally closed)
- Pipeline section with 0.259 m I.D. downstream reducer to nose of flow meter
## Problem Approach

- Computational Fluid Dynamics (CFD) solution (Navier-Stokes Equations)
- 3D block-structured grid
- Fully turbulent flow with k-eps model
## Discussion of Solution

The solution is shown in the graphics linked below. The velocity profiles at the nose of the flow meter are fairly constant beyond the boundary layers, which implies that the flow is of good quality. The computations show only a slight crosswise change in velocity field for the largest flow rate in the pipeline. Measuring the flow with the Pitot instrument is judged appropriate.

British Standards BS 6739-1986 require at least 10 diameters upstream and 5 diameters downstream the flow meter.This is satisfied by the present installation (about 18.4 diameters upstream, 5.25 diameters downstream). This condition has been also judged satisfactory by

Flowline Co.(phone 0208 207 3082), UK, that sells the flow meter DF25. The presence of the eccentric reducer is beneficial to the quality of the flow at the nose of the flow meter.## Graphic Analysis

- Geometric Model
- Velocity Profiles at front of flowmeter
- Velocity Profiles around reducer
- Velocity Profiles compared and inlet/outlet of pipeline