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Abstract

This paper analyses the influence of three different ring-type inlet duct geometries on the performance of a small 1 MW backpressure steam turbine. It examines the efficiency and pressure drop of seven turbine variants, including four spiral inlet geometries and three stages with a mass flow rate around 30 t/h. A one-pipe and two-pipe inlets are analysed from aerodynamical point of view, taking into account stator and rotor blades in three stages without the outlet. An outlet is added to the best variant. Also analysed is the occurrence of vortices in the inlets of the studied variants 1–7 as well as the efficiency, drop pressure, turbine power and mass flow. Finally, the best inlet for a 1 MW steam turbine is suggested.
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Bibliography

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Authors and Affiliations

Arkadiusz Koprowski
1
Romuald Rzadkowski
1 2

  1. Institute of Fluid Flow Machinery Polish Academy of Sciences, Fiszera 14, 80-952 Gdansk, Poland
  2. Air Force Institute of Technology, Ksiecia Bolesława 6, 01-494 Warsaw, Poland
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Abstract

The Pump As Turbine (PAT) is an important technology for low-cost micro-hydropower and energy recovery, and hence the internal hydraulics of PAT needs to be clearly understood. Additionally, during its operation, the sediments in the water increase the roughness of the internal surfaces and may alter the internal hydraulics and PAT performance similar to a centrifugal pump or Francis turbine. The researchers tried hard to perform simple modifications such as impeller blade rounding to increase the efficiency of PAT. In this paper, the developed test rig is used to analyze the performance of the impeller blade rounding and is validated with a numerical model. This numerical model is further used to study the influence of impeller blade rounding and surface roughness on internal hydraulics and PAT performance. The impeller blade rounding at the most increased the PAT efficiency by 1-1.5 % at the Best efficiency point (Q=16.8 lps), mainly due to the wake reduction on the suction side and increased flow area. With increasing the surface roughness from 0-70 μm, the PAT efficiency is decreased maximum by 4 %. The efficiency was mainly reduced due to increased hydraulic losses at flow zone and disk friction losses at the non-flow zone.
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Bibliography

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Authors and Affiliations

Rahul Gaji
1 2
ORCID: ORCID
Ashish Doshi
2
ORCID: ORCID
Mukund Bade
2
ORCID: ORCID
Punit Singh
3

  1. Annasaheb Dange College of Engineering and Technology, Ashta, India
  2. Sardar Vallabhbhai National Institute of Technology, Surat, India
  3. Centre for Sustainable Technologies, Indian Institute of Science, Bangalore, India
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Abstract

The paper presents a concept of a new turbine engine with the use of rotating isochoric combustion chambers. In contrast to previously analyzed authors’ engine concepts, here rotating combustion chambers were used as a valve timing system. As a result, several practical challenges could be overcome. An effective ceramic sealing system could be applied to the rotating combustion chambers. It can assure full tightness regardless of thermal conditions and related deformations. The segment sealing elements working with ceramic counter-surface can work as self-alignment because of the centrifugal force acting on them. The isochoric combustion process, gas expansion, and moment generation were analyzed using the CFD tool (computational fluid dynamics). The investigated engine concept is characterized by big energy efficiency and simple construction. Finally, further improvements in engine performance are discussed.
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Authors and Affiliations

Piotr Tarnawski
1
ORCID: ORCID
Wiesław Ostapski
1

  1. Institute of Machine Design Fundamentals, Warsaw University of Technology, Narbutta 84, 02-524 Warsaw, Poland

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