Abrasive Blasting Nozzle Silencer for Supersonic Jet Noise
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Solution Overview
Problem
High noise levels generated by blast nozzles during abrasive blasting processes pose a risk to worker health and cause environmental disturbances, necessitating effective noise suppression solutions.
Innovation Solution
A noise suppressed blasting system featuring a silencer with a specific geometry and dimensions that connects to the nozzle, modifying the supersonic jet to reduce noise by creating a shock structure within the silencer, resulting in a less turbulent and quieter jet.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional blast nozzles are used to accelerate particles in high-velocity jets, then cleaning and abrading effectiveness is improved, but noise levels exceed 100 dB causing hearing damage and environmental disturbance
Solution Approach 1:
A silencer device is introduced as an intermediary component between the blast nozzle and the environment. The silencer contains a supersonic jet-induced shock structure that suppresses noise generation while allowing the high-velocity particle jet to pass through and maintain cleaning effectiveness
Solution Approach 2:
The invention converts the harmful supersonic jet that causes noise into a beneficial shock structure contained within the silencer. The shock structure formed by the supersonic jet inside the silencer actually helps suppress noise rather than generate it, transforming the harmful acoustic energy into a controlled flow structure
2Object-generated harmful factors
If silencers are added to reduce noise from blast nozzles, then noise levels are suppressed, but device complexity increases
Solution Approach 1:
The silencer design utilizes parameter changes in the flow regime by allowing the formation of a shock structure at specific pressure ratios. By controlling the pressure conditions and geometry, the system achieves noise suppression through natural shock wave formation rather than complex active control mechanisms
Solution Approach 2:
The system is segmented into distinct functional components: the blast nozzle for particle acceleration and the silencer for noise suppression. This segmentation allows each component to be optimized independently, with the silencer designed specifically to contain the shock structure without interfering with the nozzle's primary function
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively suppresses noise by transforming the supersonic jet into a quieter, less turbulent flow with reduced shock formation, enhancing operational safety and reducing environmental disturbance.
Implementation Method 1
modifying the supersonic jet to reduce noise by creating a shock structure within the silencer
Data Source
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AI summary
A noise suppressed blasting system comprising: a source of blasting gas in a predetermined pressure range with abrasive particles entrained therein; a nozzle including a nozzle inlet for connection to the source of blasting gas, a nozzle outlet for emission of the blasting gas, a nozzle conduit from the nozzle inlet to the nozzle outlet including a throat therebetween with a ratio of area of the nozzle outlet to area of the throat selected to emit the blasting gas from the nozzle outlet to produce a supersonic jet; a silencer connectable to the nozzle, to receive the supersonic jet exiting the nozzle, the silencer comprising a body with a silencer conduit therethrough, the body being of sufficient length and diameter to cause a flow condition of the jet received from the nozzle outlet to be modified such that 1½ shock cells are created in a jet inside the silencer, no shock cells are created in the jet outside the silencer and a jet exits the silencer in the form of a core jet with an established turbulent shear layer thereabout and entraining an annular jet located around the core jet..