Comparative Analysis of the Drainage Effect Based on Improved Hydraulic Flushing Technology
Yong Li1, Xiaodong Zhang1, Xiao Liu1
1School of Energy Science and Engineering, Henan Polytechnic University, Jiaozuo454003, China.
ACS Omega
|December 12, 2022
Summary
Layered hydraulic flushing in composite coal seams significantly enhances underground gas drainage. This method improves gas drainage range and concentration compared to conventional techniques, offering a more effective solution for coal mine safety.
Area of Science:
- Mining Engineering
- Geotechnical Engineering
- Environmental Science
Background:
- Composite coal seams with varying deformation properties are common in China.
- Hydraulic flushing in soft coal layers can reduce stress and increase permeability, aiding gas drainage.
Purpose of the Study:
- To investigate the impact of hydraulic flushing on gas drainage in soft coal seams.
- To compare the effectiveness of layered hydraulic flushing versus conventional methods in composite coal seams.
Main Methods:
- Field investigation and verification.
- Numerical simulation and similar simulation analysis.
- Development of a fluid-solid coupling model for gas drainage.
Main Results:
- Layered flushing shows intermittent, rapid gas concentration increases, unlike conventional methods' regular attenuation.
- Numerical simulations indicate layered flushing increases effective drainage range by 8.33 m³ after 30 days.
- Layered flushing consistently achieves higher average gas concentrations (>20%) over longer periods compared to conventional methods.
Conclusions:
- Layered hydraulic flushing is a more effective technology for improving gas drainage in soft and hard composite coal seams.
- The distinct gas drainage patterns are attributed to the fluid-solid coupling dynamics influenced by layered flushing.
More Related Videos
06:26Capturing Flow-weighted Water and Suspended Particulates from Agricultural Canals During Drainage Events
Published on: November 7, 2017
16.4K
08:49Vegetated Treatment Systems for Removing Contaminants Associated with Surface Water Toxicity in Agriculture and Urban Runoff
Published on: May 15, 2017
10.7K
Related Concept Videos
01:30Underflow Gates
95
Underflow gates are vital for controlling water flow in irrigation canals. The three main types of underflow gates — vertical, radial, and drum gates — serve different purposes while ensuring effective flow management. Vertical gates move up and down, generating a free-flowing water jet; radial gates pivot to regulate the flow; and drum gates rotate for precise adjustments. The flow through these gates is influenced by downstream conditions, resulting in free or drowned outflow.Free and...
95
01:29Gradually Varying Flow
101
Gradually varying flow (GVF) in open channels describes situations where water depth changes slowly along the channel due to factors like non-uniform bed slope, channel shape variations, or obstructions. This flow type occurs when the depth adjusts gradually to balance gravitational forces, shear forces, and energy requirements, resulting in a low rate of depth change.Characteristics of Gradually Varying FlowGVF is commonly observed in natural streams, rivers, and canals, where flow depth...
101
01:21Design Example: Creating a Hydraulic Model of a Dam Spillway
267
Scaled hydraulic models of dam spillways provide a practical way to replicate and study the intricate flow dynamics of these structures. Often built to a 1:15 ratio, these models allow for observing critical water behavior, such as velocity distribution, flow patterns, and energy dissipation.
267
01:26Weir: Problem Solving
88
Water flow in open channels is often measured using hydraulic structures such as weirs, which allow precise calculation of discharge. In a rectangular channel, flow rates are measured using three types of weirs: rectangular sharp-crested, triangular sharp-crested, and broad-crested. The weir head is set at a fixed height above the channel bottom, simplifying calculations and enabling the relationship between depth and flow rate to be analyzed.For the rectangular sharp-crested weir, the flow...
88
01:19Urodynamic Studies: Uroflowmetry
283
Uroflowmetry is a non-invasive urodynamic test designed to measure various aspects of urination, including volume, flow rate, and the time to void. This test is crucial for diagnosing and assessing conditions such as bladder outlet obstruction, bladder dysfunction, incomplete bladder emptying, incontinence, and urinary tract blockages caused by benign prostatic hyperplasia (BPH) and urethral strictures.Pre-Test Instructions:Before a uroflowmetry test, patients are typically advised to drink...
283
01:27Design Example: Design of an Irrigation Channel
173
Trapezoidal channels are widely used in irrigation systems due to their cost-effectiveness and efficiency in conveying water. Trapezoidal channels feature a flat bottom and sloping sides, making them stable and easier to construct compared to other shapes. The bottom width and side slope ratio are determined based on the required flow capacity and site conditions. The side slope is kept gentle for unlined channels to prevent soil erosion.Hydraulic parameters in channel design include the flow...
173