Screw pulsation generation and control: a shock tube mechanism

Huang, Paul Xiubao; Yonkers, Sean; Hokey, David; Olenick, D.

doi:10.1533/9781782421702.2.113

Cited by 4 publications

(3 citation statements)

References 3 publications

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“…An increase in specific compression work during shock compression a t,it,UC is calculated with equation (13) and the lost specific compression work during shock expansion a t,it,OC with equation (16). The immediate isothermal power consumption required to compress the ideal gas during shock compression P σc it,UC for a given total pressure ratio σc, therefore shock intensity Ir is calculated with equation 14, for shock expansion a similar quantity is determined from equation (17).…”

Section: Calculation Methodologymentioning

confidence: 99%

“…He gives examples based on the operation of the Roots blower [14]. The same author together et al in further studying the gas pulsation, designed and developed a pulse trap method to reduce gas flow ripple and reduce noise during the process [16]. H. Wu et al created a theoretical and experimental study of the turbulence of compressed air at the discharge of a screw compressor under various discharge gas conditions [17].…”

Section: Introductionmentioning

confidence: 99%

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Ideal mathematical model of shock compression and shock expansion

2019

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Shock compression and expansion are phenomena which occur mainly in screw or vane compressors. They occur when there is an imbalance in the built-in and total pressure ratio. These are phenomena that have a negative impact on the operation of these machines and, in general, cause instability in operation, an increase in energy consumption and an overall worsening of the operational economy. The aim of this article is to present newly discovered information regarding making work processes of said compressors more effective, as in many cases, shock phenomena are subconsciously underestimated. The set aim was reached by creating an ideal simulation of isothermal compression of an ideal gas with the implementation of shock phenomena, which were performed on a screw compressor with the operating pressure 7 bar and a flow performance of 3 440 l min−1. Based on the simulations performed, the hypotheses which set forth that the impact of shock phenomena ultimately leads to a sudden increase in compressor power consumption were confirmed. E.g. at 6 bar, the instantaneous power consumption increases by about 5.74% during shock compression and by about 55.95% during shock expansion. This paper deals with new insights and at the same time presents the follow-up research.

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Section: Calculation Methodologymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Ideal mathematical model of shock compression and shock expansion

2019

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“…Wu et al performed a theoretical and experimental study of the screw compressor exhaust airflow ripple considering the effects of condition and speed on discharge pressure pulsation [3]. Huang et al studied gas pulsation and proposed the pulsation trap method to reduce compressor airflow ripple and noise [4]. Mujic et al proposed that the discharge port was an important parameter influencing the gas pulsations and the gas pulsations amplitude can 2 Mathematical Problems in Engineering be reduced by optimization of the port shape [5].…”

Section: Introductionmentioning

confidence: 99%

Flow Field Simulation and Noise Control of a Twin-Screw Engine-Driven Supercharger

Wang¹,

Li²,

Qiang-qiang³

et al. 2016

Mathematical Problems in Engineering

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With the advantages of good low-speed torque capability and excellent instant response performance, twin-screw superchargers have great potential in the automobile market, but the noise of these superchargers is the main factor that discourages their use. Therefore, it is important to study their noise mechanism and methods of reducing it. This study included a transient numerical simulation of a twin-screw supercharger flow field with computational fluid dynamics software and an analysis of the pressure field of the running rotor. The results showed that overcompression was significant in the compression end stage of the supercharger, resulting in a surge in airflow to a supersonic speed and the production of shock waves that resulted in loud noise. On the basis of these findings, optimization of the supercharger is proposed, including expansion of the supercharger exhaust orifice and creation of a slot along the direction of the rotor spiral normal line at the exhaust port, so as to reduce the compression end pressure, improve the exhaust flow channel, and weaken the source of the noise. Experimental results showed that the noise level value of the improved twin-screw supercharger was significantly lower at the same speed than the original model, with an average decrease of about 5 dB (A).

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