# Intrinsically Safe Drone Propulsion System for Underground Coal Mining Applications: Computational and Experimental Studies

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## Abstract

**:**

## 1. Introduction

## 2. Design Strategy of an Intrinsically Safe Drone

**Figure 2.**Multirotor propulsion chain diagram [24].

## 3. Propulsion System Performance Measurement Setup

## 4. Mechanical Coupler Design and Testing

## 5. Motor’s Enclosure Thermal Effects

#### 5.1. Casing Thermal Effects on the Propulsion System Performance

#### 5.2. Radial Heat Sink for Propulsion System Cooling

_{w}= 393.15 K and various T

_{inf}are shown in Figure 11. Figure 13 shows the heat-sink fin temperature distribution for air temperature T

_{inf}= 298.15 K and various wall temperatures, T

_{w}. Fins of 15 mm and 30 mm are included in the results. Generally, changing the boundary condition changes the temperature distribution. The 15 mm fin is more efficient than the 30 mm, as the temperature is reduced smoothly until the tip of the fin. For the 30 mm fin, it can be seen that most of the fin is not doing any role in heat reduction, and also, it is more weight to be added with less efficiency. Therefore, the 15 mm fin will be installed on the motor, and its performance will be investigated.

#### 5.3. Thermal Imaging of the Propulsion System

## 6. Motor Enclosure Flow Blockage and Spinner Design

## 7. Conclusions

## Author Contributions

## Funding

## Institutional Review Board Statement

## Informed Consent Statement

## Data Availability Statement

## Acknowledgments

## Conflicts of Interest

## References

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**Figure 11.**Heat-sink fin temperature distribution for T

_{w}= 393.15 K and various T

_{inf}, 15 mm fin (

**left**) and 30 mm fin (

**right**).

**Figure 12.**Heat-sink fin temperature distribution for T

_{inf}= 298.15 K and various T

_{w}, 15 mm fin (

**left**) and 30 mm fin (

**right**).

τ | 0.13 | 0.27 | 0.42 | 0.57 | 0.72 | 0.82 |
---|---|---|---|---|---|---|

Motor without casing 50% RPM | ||||||

Motor without casing 75% RPM | ||||||

Motor with casing 50% RPM | ||||||

Motor with casing 75% RPM | ||||||

Motor with casing and heat sink CPD 50% RPM | ||||||

Motor with casing and heat sink CPD 75% RPM | ||||||

Motor with casing and heat sink PD 50% RPM | ||||||

Motor with casing and heat sink PD 75% RPM |

L1 (55 mm) | L2 (36.6 mm) | L3 (27.5 mm) | |
---|---|---|---|

K1 (1) | $-\frac{{x}^{2}}{110}+x$ | $\frac{3\times x}{2}-\frac{9\times {x}^{2}}{440}$ | $2\times x-\frac{2\times {x}^{2}}{55}$ |

K2 (0.8) | $-\frac{{x}^{2}}{165}+\frac{5\times x}{6}$ | $\frac{5\times x}{4}-\frac{3\times {x}^{2}}{220}$ | $\frac{5\times x}{3}-\frac{4\times {x}^{2}}{165}$ |

K3 (0.6) | $\frac{5\times x}{7}-\frac{3\times {x}^{2}}{770}$ | $\frac{15\times x}{14}-\frac{27\times {x}^{2}}{3080}$ | $\frac{10\times x}{7}-\frac{6\times {x}^{2}}{385}$ |

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**MDPI and ACS Style**

Aboelezz, A.; Wetz, D.; Lehr, J.; Roghanchi, P.; Hassanalian, M.
Intrinsically Safe Drone Propulsion System for Underground Coal Mining Applications: Computational and Experimental Studies. *Drones* **2023**, *7*, 44.
https://doi.org/10.3390/drones7010044

**AMA Style**

Aboelezz A, Wetz D, Lehr J, Roghanchi P, Hassanalian M.
Intrinsically Safe Drone Propulsion System for Underground Coal Mining Applications: Computational and Experimental Studies. *Drones*. 2023; 7(1):44.
https://doi.org/10.3390/drones7010044

**Chicago/Turabian Style**

Aboelezz, Ahmed, David Wetz, Jane Lehr, Pedram Roghanchi, and Mostafa Hassanalian.
2023. "Intrinsically Safe Drone Propulsion System for Underground Coal Mining Applications: Computational and Experimental Studies" *Drones* 7, no. 1: 44.
https://doi.org/10.3390/drones7010044