Direct numerical simulations (DNS) and experiments are carried out to study fully developed turbulent pipe flow at Reynolds number Rec ≈ 7000 based on centreline velocity and pipe diameter. The agreement between numerical and experimental results is excellent for the lower-order statistics (mean flow and turbulence intensities) and reasonably good for the higher-order statistics (skewness and flatness factors). To investigate the differences between fully developed turbulent flow in an axisymmetric pipe and a plane channel geometry, the present DNS results are compared to those obtained from a channel flow simulation. Beside the mean flow properties and turbulence statistics up to fourth order, the energy budgets of the Reynolds-stress components are computed and compared. The present results show that the mean velocity profile in the pipe fails to conform to the accepted law of the wall, in contrast to the channel flow. This confirms earlier observations reported in the literature. The statistics on fluctuating velocities, including the energy budgets of the Reynolds stresses, appear to be less affected by the axisymmetric pipe geometry. Only the skewness factor of the normal-to-the-wall velocity fluctuations differs in the pipe flow compared to the channel flow. The energy budgets illustrate that the normal-to-the-wall velocity fluctuations in the pipe are altered owing to a different ‘impingement’ or ‘splatting’ mechanism close to the curved wall.

A study of pressure oscillations occurring in small centrifugal compressor systems without a plenum is presented. Active and passive surge control were investigated theoretically and experimentally for systems with various inlet and discharge piping configurations. The determination of static and dynamic stability criteria was based on Greitzer’s (1981) lumped parameter model modified to accommodate capacitance of the piping. Experimentally, passive control using globe valves closely coupled to the compressor prevented the occurrence of surge even with the flow reduced to zero. Active control with a sleeve valve located at the compressor was effective but involved a significant component of passive throttling which reduced the compressor efficiency. With an oscillator connected to a short side branch at the compressor, effective active control was achieved without throttling. Both methods of active control reduced the flow rate at surge onset by about 30 percent. In general, the experiments qualitatively confirmed the derived stability criteria.

A study of pressure oscillations occurring in small centrifugal compressor systems without a plenum is presented. Active and passive surge control were investigated theoretically and experimentally for systems with various inlet and discharge piping configurations. The determination of static and dynamic stability criteria was based on Greitzer’s (1981) lumped parameter model modified to accommodate capacitance of the piping. Experimentally, passive control using globe valves closely coupled to the compressor prevented the occurrence of surge even with the flow reduced to zero. Active control with a sleeve valve located at the compressor was effective but involved a significant component of passive throttling which reduced the compressor efficiency. With an oscillator connected to a short side-branch at the compressor, effective active control was achieved without throttling. Both methods of active control reduced the flow rate at surge onset by about 30%. In general, the experiments qualitatively confirmed the derived stability criteria.

The effects of pulsating flow on a single-rotor turbine meter with a rotor response parameter greater than unity were investigated experimentally. Oscillating velocities and pressures at various pipe cross-sections were measured which enabled characterization of flow properties at the turbine meter and their effect on meter error. Measurements confirmed that meter error depends primarily on the velocity amplitude of the flow pulsation at the rotor. Moreover, it was shown that the velocity amplitude at the rotor results from the system response, which is determined by the system geometry, pulsation frequency, flow velocity, and sound speed. Lastly, a technique was developed to determine the meter error from measurements of dynamic pressure in the pipe upstream or downstream of the turbine meter.

Steam furnaces encountered in chemical and power generation plants often experience a maldistribution of steam temperature at furnace tube outlets despite attempts to ensure good flow distribution in these tubes from the inlet feed header. An investigation of an existing tube bank configuration was carried out utilizing field measurements, a CFD analysis of the thermal/flow field, flow experiments with a 1:7 scale laboratory model using air as the working fluid, and a 1-D analysis of the temperature/flow distribution. The results indicate that although the inlet header does not actually run through the furnace, heat transfer by conduction from the tube walls to the inlet header wall causes preheating of the incoming steam, resulting in a substantial increase in steam temperature towards the end of the header. This steam temperature maldistribution at the inlet to the tubes persists along the tubes and manifests itself as a similar maldistribution in the tube skin wall temperatures. The latter has an impact on the system integrity if the skin wall temperature exceeds the metallurgical limit of the tube material used.