Pressure recovery during pressure reduction experiment with large-scale liquid hydrogen tank

The paper presents detailed measurements of the incompressible flow at the exit of a large-scale 90-degree curved diffuser with strong curvature and significant stream-wise variation in the cross-section aspect ratio. The diffuser flow path approximates the so-called fish-tail diffuser utilized on small gas turbine engines for the transition between the centrifugal impeller and the combustion chamber. Five variations of the inlet boundary layer are considered. The results provide insight into several aspects of the diffuser flow including: the effect of flow turning on diffusion performance; the dominant structures influencing the flow development in the diffuser; and the effect of the inlet boundary layer integral parameters on the diffusion performance and the exit velocity field. The three-dimensional velocity distribution at the diffuser exit is found to be sensitive to circumferentially uniform alterations to the inlet boundary layer. In contrast, circumferential variations in the inlet boundary layer are observed to have only secondary effects on the velocity field at the diffuser exit. The static pressure recovery is observed to be comparable to the published performance of conical diffusers with equivalent included angle and area ratios. Furthermore, both the static pressure recovery and the total pressure losses are observed to be relatively insensitive to variations in the inlet boundary layer. The physical mechanisms dominating the flow development in the diffuser are discussed in light of these observations.

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A new prediction model for hydrostatic pressure reduction of anti-gas channeling cement slurry based on large-scale physical modeling experiments

Journal of Petroleum Science and Engineering ◽

10.1016/j.petrol.2018.09.035 ◽

2019 ◽

Vol 172 ◽

pp. 259-268

Author(s):

Yijin Zeng ◽

Peiqing Lu ◽

Shiming Zhou ◽

Laiyu Sang ◽

Rengguang Liu ◽

...

Keyword(s):

Hydrostatic Pressure ◽

Prediction Model ◽

Physical Modeling ◽

Large Scale ◽

Pressure Reduction ◽

Cement Slurry ◽

Gas Channeling

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Thermodynamic and Economic Feasibility of Energy Recovery from Pressure Reduction Stations in Natural Gas Distribution Networks

Energies ◽

10.3390/en13174453 ◽

2020 ◽

Vol 13 (17) ◽

pp. 4453 ◽

Cited By ~ 1

Author(s):

Piero Danieli ◽

Gianluca Carraro ◽

Andrea Lazzaretto

Keyword(s):

Natural Gas ◽

Energy Recovery ◽

Internal Combustion Engines ◽

Large Scale ◽

Net Present Value ◽

Energy Content ◽

Distribution Networks ◽

Economic Feasibility ◽

Pressure Reduction ◽

Gas Distribution

A big amount of the pressure energy content in the natural gas distribution networks is wasted in throttling valves of pressure reduction stations (PRSs). Just a few energy recovery systems are currently installed in PRSs and are mostly composed of radial turboexpanders coupled with cogeneration internal combustion engines or gas-fired heaters providing the necessary preheating. This paper clarifies the reason for the scarce diffusion of energy recovery systems in PRSs and provides guidelines about the most feasible energy recovery technologies. Nine thousand PRSs are monitored and allocated into 12 classes, featuring different expansion ratios and available power. The focus is on PRSs with 1-to-20 expansion ratio and 1-to-500 kW available power. Three kinds of expanders are proposed in combination with different preheating systems based on boilers, heat pumps, or cogeneration engines. The goal is to identify, for each class, the most feasible combination by looking at the minimum payback period and maximum net present value. Results show that small size volumetric expanders with low expansion ratios and coupled with gas-fired heaters have the highest potential for large-scale deployment of energy recovery from PRSs. Moreover, the total recoverable energy using the feasible recovery systems is approximately 15% of the available energy.

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