Development of Low-Specific Speed New-Type Hydraulic Turbine Equipped with Volute: Numerical Investigation and Performance Prediction

Abstract In order to improve the mechanical properties of nitrate ester plasticized polyether (NEPE) propellants, 3-allylic hydantoin was synthesized by hydantoin, potassium hydroxide and 3-bromopropene, and then a new type of intermediate polymer bonding agent (NPBA) was synthesized by 3-allylic hydantoin, acrylonitrile, hydroxyethyl acrylate and dimethylaminoethyl methacrylate. At the same time, two traditional neutral polymer bonding agents were synthesized for comparative study. Through the contact angle test, the bond performance prediction shows that: compared with the two traditional bond agents, the bond work between the new bond agent and oxidant (ammonium nitrate, ammonium perchlorate) is greater, indicating that the bond between the new bond agent and oxidant is stronger.

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Design and Analysis of Energy-Efficient Low-Flow Centrifugal Compressors

Journal of Energy Resources Technology ◽

10.1115/1.4046525 ◽

2020 ◽

Vol 142 (8) ◽

Author(s):

Cheng Xu ◽

Lei Chen ◽

Ryoichi S. Amano

Keyword(s):

Flow Coefficient ◽

Low Flow ◽

Design Strategies ◽

Design Features ◽

Centrifugal Compressors ◽

Design Studies ◽

Low Specific Speed ◽

Specific Speed ◽

And Performance ◽

Low Flow Coefficient

Abstract With the increasing demands of energy-saving from industries, the low-flow coefficient and low specific speed centrifugal compressors have gained more attention. The design of this type of compressor faced many challenges, for example, high secondary flow losses, high tip leakage losses, and low exit width based on a Reynolds number. The design also lacks a reliable database for preliminary studies. The impeller design studies were limited. Most designs for low-flow coefficient and low specific speed compressor follow the traditional methods. This paper presents design studies and discusses some unique design features to improve performance of this type of compressor. The detail computational fluids dynamics (CFD) results are presented to demonstrate the success of the design strategies. A prototype compressor for fuel cell applications was built, and performance tests were performed. The test results are compared with those of the computational analysis, and the agreement is reasonably satisfactory. The compressor meets the customer's performance goals. The design features can be used for future low-flow coefficient and low specific speed centrifugal compressor design.

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The Role of Blade Sinusoidal Tubercle Trailing Edge in a Centrifugal Pump with Low Specific Speed

Processes ◽

10.3390/pr7090625 ◽

2019 ◽

Vol 7 (9) ◽

pp. 625 ◽

Cited By ~ 5

Author(s):

Bowen Li ◽

Xiaojun Li ◽

Xiaoqi Jia ◽

Feng Chen ◽

Hua Fang

Keyword(s):

Centrifugal Pump ◽

Pressure Pulsation ◽

Suction Side ◽

High Amplitude ◽

Pressure Pulsations ◽

Trailing Edge ◽

Low Specific Speed ◽

Specific Speed ◽

And Performance ◽

The Impact

Pressure pulsations may cause high-amplitude vibrations during the process of a centrifugal pump. The trailing edge shape of the blade has a critical influence on the pump’s pressure fluctuation and hydraulic characterization. In this paper, inspired by the humpback whale flipper, the authors research the impact of applying the sinusoidal tubercles to the blade suction side of the trailing edge. Numerical calculation and experiments are carried out to investigate the impact of the trailing edge shape on the pressure pulsations and performance of a centrifugal pump with low specific speed. Two designed impellers are tested, one is a sinusoidal tubercle trailing edge (STTE) impeller and the other is the original trailing edge (OTE) prototype. The detailed study indicates that the sinusoidal tubercle trailing edge (STTE) reduces pressure pulsation and enhances hydraulic performance. In the volute tongue region, the pressure pulsation amplitudes of STTE at fBPF decrease significantly. The STTE impeller also effectively changes the vortex structure and intensity in the blade trailing edge area. This investigation will be of great benefit to the optimal design of pumps.

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