Next Article in Journal
Temporal Evolution of Split-Injected Fuel Spray at Elevated Chamber Pressures
Previous Article in Journal
Conceptual Design of IoT-Based AMR Systems Based on IEC 61850 Microgrid Communication Configuration Using Open-Source Hardware/Software IED
Previous Article in Special Issue
Numerical Analysis of Roadway Rock-Burst Hazard under Superposed Dynamic and Static Loads
Open AccessArticle

Study on Thermal Energy Conversion Theory in Drilling Process of Coal and Rock Mass with Different Stresses

State Key Laboratory of Mining Disaster Prevention and Control Co-Founded by Shandong Province and the Ministry of Science and Technology, Shandong University of Science and Technology, Qingdao 266590, China
*
Author to whom correspondence should be addressed.
Energies 2019, 12(22), 4282; https://doi.org/10.3390/en12224282
Received: 18 September 2019 / Revised: 6 November 2019 / Accepted: 7 November 2019 / Published: 10 November 2019
(This article belongs to the Special Issue Advanced Technologies for Energy Exploitation of Coals)
In view of the problem that the evolutionary mechanism of bit temperature during the drilling process is still unclear and the influencing factors are complex, this paper analyzes the causes of heat generation and the factors of heat production when the drill bit interacts with the coal and rock mass. Considering the stress field distribution of coal and rock mass and the dynamic characteristics of drilling, a three-dimensional mechanical structure model of bit drilling is established in this paper, based on the energy conservation theory and introducing the friction heat micro-distribution mechanism. The corresponding relationship between coal stress and the bit temperature variation rate is obtained in this paper. Therefore, the temperature rise condition model and the coal stress identification model can be verified, combined with the existing experimental data. The result shows that the temperature of bit drilling is affected by factors such as bit geometry and drilling parameters, as well as the strength and stress state of the coal and rock. Without considering other factors, the rate of increase in bit temperature is proportional to the stress of the coal and rock mass. Based on the research results, the temperature rate of the drill bit can be used as an index to identify the stress areas of coal and rock mass. Research results provide a theoretical basis for the identification of high-stress risk areas in coal mines. View Full-Text
Keywords: drilling chip temperature method; bit; temperature rate; stress of coal and rock drilling chip temperature method; bit; temperature rate; stress of coal and rock
Show Figures

Graphical abstract

MDPI and ACS Style

Qiu, P.; Li, X.; Ning, J.; Wang, J.; Yang, S. Study on Thermal Energy Conversion Theory in Drilling Process of Coal and Rock Mass with Different Stresses. Energies 2019, 12, 4282.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop