CC BY
11Original article / Оригинальная статья УДК 331.45
DOI: https ://doi.org/10.21285/2500-1582-2019-3-316-326
Research and analysis of frequency regulation and operation efficiency of the main mine ventilator
© Ma Heng1, Guo Yao2, Liu Xiang3
1,2,3School of safety science and engineering, Liaoning Technical University, Fuxin, Liaoning, China 1,2,3Liaoning Key Laboratory of mine safety, Fuxin, Liaoning, China
Abstract: The main mine ventilator plays a vital role for safety. Its operating conditions have a direct impact on safety and reliability of the mine ventilation system. In order to study the frequency regulation and operating efficiency of the main ventilator, the paper uses a self-developed ventilator platform to determine performance parameters of different sets of frequencies and blade angles under the actual operating state of the ventilator, and uses an ordinary least squares method to process the data. The curve of the ventilator is used to identify efficiency of the ventilator.
Key words: ventilator; frequency conversion adjustment, operating efficiency, experiment, curve
Information about the article: Received March 20, 2019; accepted for publication June 27, 2019; available online September 30, 2019.
For citation: Ma Heng, Guo Yao, Liu Xiang. Research and analysis of frequency regulation and operation efficiency of the main mine ventilator. XXI century. Technosphere Safety. 2019;4(3):316-326. (In Russian) DOI: 10.21285/2500-15822019-3-316-326.
Анализ частотного регулирования и эффективности работы основного шахтного вентилятора
Ма Хенг1, Гу Яо2, Лиу Сян3
12 3
,, Школа безопасности и инжиниринга, Ляонинский технический университет, Фусинь, Ляонин, Китай 1,2,3Ляонинская лаборатория исследования безопасности шахт, Фусинь, Ляонин, Китай
Резюме: Основной шахтный вентилятор играет важную роль в обеспечении безопасности работы шахты. Условия его функционирования оказывают влияние на безопасность и надежность системы вентиляции шахты. С целью исследования частотного регулирования и эффективности работы шахтного вентилятора был разработан специальный стенд. С его помощью была исследована работа вентилятора при различных значениях частоты и углах наклона лопастей. Метод наименьшего квадрата был использован для обработки данных. Кривая вентилятора показывает эффективность его работы.
Ключевые слова: вентилятор, преобразование частоты, эффективность работы, эксперимент, кривая
Информация о статье: Дата поступления 20 марта 2019 г.; дата принятия к печати 27 июня 2019 г.; дата онлайн-размещения 30 сентября 2019 г.
Формат цитирования: Ма Хенг, Гу Яо, Лиу Сян. Анализ частотного регулирования и эффективности работы основного шахтного вентилятора. XXI век. Техносферная безопасность. 2019;4(3):316—326. DOI: 10.21285/2500-1582-2019-3-316-326.
1. Introduction
The current traditional adjustment sys-
tem of the main mine ventilator is based on the adjustment of the angle of the damper or the ventilator blade. This adjustment method
increases the volume of electric energy and causes inconveniences. The frequency conversion technology involves changing the air flow volume by adjusting the rotational speed of the ventilator, changing the output power of
Ma Heng, Guo Yao, Liu Xiang. Research and analysis of frequency regulation and operation efficiency
of the main mine ventilator
Ма Хенг, Гу Яо, Лиу Сян. Анализ частотного регулирования и эффективности работы
основного шахтного вентилятора
the ventilator. Frequency conversion is the most efficient method of ventilator air flow adjustment. The frequency conversion can adjust the air volume quickly, so that to keep the ventilator in an operating state, and save energy which in compliance with the national policies on energy conservation. This study illustrates future trends of the development of main mine ventilators [1-6].
2. The ventilator proportion law
Pressure H, flow rate Q and power N of the ventilator are proportional to the number of revolutions n, dimension D and air density p. The relationship between motor speed n and frequency f is as follows:
n =
_60f {1 - s )
(1)
where p - the stator magnetic field logarithm of the motor; s - the slip of the motor.
According to fluid mechanics, the theoretical equation of ventilation is as follows:
n,
ft = Q f Q2
H}2
V H2 J
t
V N2 J
(2)
It can be seen from equation (2) that if air flow volume Q, wind pressure H, and power N at a certain frequency are measured, the frequency can be adjusted freely, and air flow volume Q, wind pressure H, and power N should be generated.
3. Experimental study on frequency conversion characteristics of the mine ventilator
Similar conditions for the ventilator. To make the experimental model of the ventilator real, the similarity between the experimental model and the prototype one in terms of the cross-section shape and the airflow should be ensured (geometric similarity, kinematic similarity and power similarity).
Experimental devices of the main ventilator performance test. The experimental test system, which includes the adjustment device and the measuring device, is designed to base its prototype on the actual axial flow ventilator and the cylindrical roadway, for yielding experimental relationship between the ventilator adjustment frequency and the operating efficiency. The prototype-to-model similarity ratio is 20:1. The inner diameter of the simulated tunnel is 200 mm and the length is 4 m. The experimental system is shown in Fig. 1.
Rectifier
Board
Wind
speed probe
Pitot
Power supply
Ventilation multi-function parameter meter
Dynamometer
Fig. 1. Schematic diagram of the experimental device system Рис 1. Схема экспериментального устройства
Test location and method.
1) Position and method of working condition adjustment.
According to the specific positioning of the ventilator and the simulated roadway, the position of the working condition adjustment is determined at the simulated roadway 4 m away from the ventilator outlet. The working condition adjustment method adds the wooden board, which is a derivative of resistance increase method. The opening state decreases from maximum as the number of wood boards increases, which is shown in Fig. 1, section A-A.
2) Position and method of simulating roadway wind speed measurement.
The test air flow volume position is set at 1m away from the ventilator port in the simulated roadway to ensure the stability of the wind flow and the accuracy of wind speed measurement (see the B-B section in Fig. 1).
3) Position and method of static pressure test.
The static pressure position is set at the air inlet of the ventilator, and the Pitot tube is fixed and placed in the center of the simulated roadway. The horizontal tube axis is parallel to the wind direction and against the wind flow. It is used to measure the relative static pressure of the ventilator inlet, and the atmospheric pressure is measured by a barometer (see the C-C section in Fig. 1).
Experimental test process.
1) Adjustment of the blade installation angle to -3°, and the frequency converter to 50.0 Hz, and maximum opening of the damper. After the error correction, starting the ventilator and adding the wooden board for testing to obtain relevant experimental data of at -3° blade angle under 50.0 Hz. Adjustment of frequency to 47.5 Hz, 45.0 Hz, 42.5 Hz, 40.0 Hz, 37.5 Hz, 35.0 Hz, 32.5 Hz, 30.0 Hz, so that the ventilator-related parameters of different frequencies at -3° blade angle can be obtained. Shutting down the ventilator.
2) Adjustment of the ventilator blade angle to 0° and +3°, and using the same method, testing of the ventilator-related parameters of different frequencies at 0° and +3° blade angle.
Recording and calculation of experiment results. The data were recorded and calculated according to AQ1011-2005 "Safety Inspecting-Testing Specification of Main Using Fan System for mine", and 27 sets of experimental data were obtained.
4. Analysis of experiment results of frequency conversion characteristics of the mine ventilator
Processing of experimental data. Due to variations in equipment, test environment, test methods, etc., there is an inevitable error in the test data. Therefore, in the data analysis and processing, it is important to minimize errors [9].
In order to ensure accuracy, the performance curve and function equation should be obtained during testing. Operating parameters should be no less than 6~8.using [12]. The software adjustment numerical method can be used. The least squares method can be used to minimize the sum of squares of the errors, and obtain unknown data [13].
Analysis of the air flow volume Q-efficiency n at different frequencies. For observing the characteristic relationship between the air flow volume and efficiency of the inverter ventilator, the ventilator experiment data is collected under conditions of its electricity operating frequencies of 50 Hz, 45 Hz, 40 Hz, 35 Hz and 30 Hz at -3°, 0° and +3° blade angles.
The least square method is used to fit the experimental data, and the air flow volume Q-Efficiency n curve of each frequency (50 Hz, 45 Hz, 40 Hz, 35 Hz, 30 Hz) of the 3°, 0° and +3° blade angles of the main ventilator is fitted. As shown in Fig. 2-4.
318
ISSN 2500-1582
(print) ISSN 2500-1574 (online)
XXI ВЕК. ТЕХНОСФЕРНАЯ БЕЗОПАСНОСТЬ XXI CENTURY. TECHNOSPHERE SAFETY
2019;4(3):316-326
Ma Heng, Guo Yao, Liu Xiang. Research and analysis of frequency regulation and operation efficiency
of the main mine ventilator
Ма Хенг, Гу Яо, Лиу Сян. Анализ частотного регулирования и эффективности работы
основного шахтного вентилятора
Fig. 2. Air flow volume Q-efficiency n curve at a blade angle equal to -3° at different frequencies
Рис. 2. Кривая Q-эффективности n объема воздушного потока при величине угла лопасти -3 °
и разных значениях частоты
40
50
60
70
Q/m
80
90
Fig. 3. Air flow volume Q-efficiency n curve at a blade angle equal to 0° at different frequencies
Рис. 3. Кривая Q- эффективности n объема воздушного потока при величине угла лопасти 0 °
и разных значениях частоты
Fig. 4. Air flow volume Q-efficiency n curve at a blade angle equal to -3° at different frequencies
Рис. 4. Кривая Q- эффективности n объема воздушного потока при величине угла лопасти -3
и разных значениях частоты
о
The following rules can be drawn from Fig. 2-4:
1) At different frequencies of the same blade angle, the variation trends of the air flow volume Q-efficiency n curves are consistent, indicating that the air flow volume Q-efficiency П curves at different frequencies of the same blade angle show a level of similarity;
2) With the increase of air flow volume Q, the efficiency n first increases, and then decreases gradually after the highest efficiency point, and the highest efficiency points corresponding to different frequencies are different; as the operating frequency increases, the highest efficiency point increases simultaneously. Tab.1 shows the highest efficiency points for each frequency at different blade angles.
Comparing Fig. 2-4, it can be seen that similarity of the Q-efficiency n curve at the +3° blade angle is more significant than at -3° and 0°, but there are still no strict equal ratios due to the calculation according to the law of proportionality based on the rotational speed only and not taking into account the heat loss of the motor. When the frequency is different, the heat loss of the motor varies.
Analysis of air flow volume Q-efficiency n under different blade angles. The least square method is used to adjust the experimental data, and different blade angles (-3°, 0°, +3°) are respectively adjusted when the operating frequency is 50 Hz, 45 Hz, 40 Hz, 35 Hz and 30 Hz. The air flow volume Q-efficiency n curves are shown in Fig. 5-9.
Table 1
The highest efficiency point corresponding to each frequency at different blade angles
Таблица 1
Наивысшее значение эффективности для каждого значения частоты _и разных углов лопасти_
Operating frequency, Hz Blade angle, -3° Blade angle, 0° Blade angle, +3°
30 52.02% 61.63% 62.99%
35 60.60% 62.65% 64.80%
40 66.22% 66.38% 68.09%
45 62.84% 67.93% 71.61%
50 69.06% 70.46% 78.64%
Fig. 5. Air flow volume Q-efficiency n curve at different blade angles at 50 Hz
Рис. 5. Кривая Q-эффективности объема воздушного потока при разных углах наклона лопасти
и частоте 50 Гц
Ma Heng, Guo Yao, Liu Xiang. Research and analysis of frequency regulation and operation efficiency
of the main mine ventilator
Ма Хенг, Гу Яо, Лиу Сян. Анализ частотного регулирования и эффективности работы
основного шахтного вентилятора
Q/m3 -min"1
Fig. 6. Air flow volume Q-efficiency n curve at different blade angles at 45 Hz
Рис. 6. Кривая Q-эффективности объема воздушного потока при разных углах наклона лопасти
и частоте 45 Гц
Q/m3min1
Fig. 7. Air flow volume Q-efficiency n curve at different blade angles at 40 Hz
Рис. 7. Кривая Q-эффективности объема воздушного потока при разных углах наклона лопасти
и частоте 40 Гц
Fig. 8. Air flow volume Q-efficiency n curve at different blade angles at 35 Hz
Рис. 8. Кривая Q-эффективности объема воздушного потока при разных углах наклона лопасти
и частоте 35 Гц
65 60 55 50 45 40 35
30
35
40
45
50
55
60
Q/m
Fig. 9. Air flow volume Q-efficiency n curve at different blade angles at 30 Hz
Рис. 5. Кривая Q-эффективности объема воздушного потока при разных углах наклона лопасти
и частоте 30 Гц
The following rules can be derived from Fig. 5-9:
1) With an increase in the air flow volume Q, efficiency n increases and decreases gradually;
2) Under different operating angles of the blade with the same operating frequency, the highest efficiency point is different; as the blade angle increases, the highest efficiency point increases.
At the same blade angle, when the ventilator operating frequency is 50 Hz, the efficiency is higher than that of other frequen-
cies, which is one of the reasons why most mine ventilators operate at a load of 50 Hz. As shown in Tab. 2, when the ventilator is fully loaded (50 Hz), the error squared sum and the mean variance of the curve at different blade angles (-3°, 0°, +3°) are obtained by data adjustment. It can be seen from Tab. 2 that the average variance (Adj.R-Square) at +3° blade angle is close to 1, and the sum of squared errors is small enough to meet the requirements of accuracy, that is, the curve has the highest accuracy at 50 Hz at +3° blade angle.
Table 2
The square error sum and the mean variance of the running error of the main ventilator
at full load (50Hz) at different blade angles
Таблица 2
Сумма квадратов ошибок и средняя дисперсия погрешности работы основного вентилятора при полной нагрузке (50 Гц) под разными углами наклона лопастей
Blade angle SSE Adj.R-Square
-3° 20.2475 0.88818
0° 35.7542 0.85571
+3° 20.78274 0.97206
Ma Heng, Guo Yao, Liu Xiang. Research and analysis of frequency regulation and operation efficiency
of the main mine ventilator
Ма Хенг, Гу Яо, Лиу Сян. Анализ частотного регулирования и эффективности работы
основного шахтного вентилятора
Frequency conversion curve of the main ventilator. In order to observe the influence of the blade angle and frequency on the ventilator air flow volume curve, the experimental data of operating frequencies 40 Hz, 45 Hz, 50 Hz at -3° blade angle and operating frequencies 35 Hz, 40 Hz, 45 Hz at 0° blade angle were used (Fig. 10). The experimental data on operating frequencies 40 Hz, 45 Hz, and 50 Hz at 0° blade angle and the experimental data on operating frequencies 35 Hz, 40 Hz, and 45 Hz at +3° blade angle were used to adjust the air flow volume Q-wind pressure H curve, as shown in Fig. 11.
It can be concluded that at 0° blade angle, the frequency has changed from 35 Hz to 40 Hz and then to 45 Hz, and the wind pressure curve moves to the upper right. At the angle of -3°, the frequency changed from 50 Hz to 45 Hz. At 40 Hz, the wind pressure
curve moves to the lower left, and the wind pressure curves of the frequencies at the two blade angles have an interpenetrating tendency.
It can be concluded from Fig. 11 that at the blade angle of +3°, the frequency conversion operation of the ventilator is changed from 35 Hz to 40 Hz and then to 45 Hz, and the wind pressure curve moves to the upper right. At 0° blade angle, the frequency conversion operation of the ventilator is converted from 50 Hz to 45 Hz and then to 40 Hz, the wind pressure curve moves to the lower left, and the two ends of the 45 Hz at 0° pressure curve have intersections with the +3°40 Hz pressure curve and the 45 Hz at +3° pressure curve. The 50 Hz at 0° pressure curve and the 45 Hz at +3° pressure curve have an intersection.
Fig. 10. -3° and 0° air flow volume Q-wind pressure H frequency conversion curve Рис. 10. Кривая Q-эффективности объема воздушного потока при разных углах лопасти при 50 Гц
500 450 400 350 £ 300 ^ 250 200 150 100 ■
+3°, 45Hz
35 40 45 50 55 60 65 70 75 80 85 90 95
Q/m
Fig. 11. 0° and +3° air flow volume Q-wind pressure H frequency conversion curve Рис. 11. Кривая преобразования частоты давления Н объема воздуха при 0 ° и + 3
Comparing Fig. 10 and Fig. 11, it can be concluded that the pressure curves at a large blade angle with decreasing frequencies would approach to the pressure curves at a small blade angle with increasing frequencies, and intersection points may appear.
In order to observe the influence of the blade angle and frequency adjustments on the ventilator performance curve, the air flow volume-efficiency curves in the above two cases were adjusted (Fig. 12-13).
It can be concluded that when the frequency of the ventilator operation changes
70 65 60 -p 55 50 45
from 35 Hz to 40 Hz and then to 45 Hz under the 0° blade angle, the efficiency curve moves to the upper right. When the frequency of the ventilator operation changes from 50 Hz to 45 Hz and then to 40 Hz under the -3° blade angle, the wind pressure curve moves to the lower left, indicating that the efficiency is gradually reduced as the frequency falls from large to small under a large blade angle, and the efficiency is gradually increased as the frequency increases from small to large under a small blade angle.
3°, 50Hz
40
40 45 50 55 60 65 70 75 80 85
Q/n
Fig. 12. -3° and 0° air flow volume Q-efficiency n conversion curve Рис. 12. Кривая преобразования Q-эффективности n объема воздуха при -3 ° и 0 °
о-*
75 70 65 60 55 50 45 40 35
30
+3°, 45Hz
0°, 50Hz
+3°, 40Hz +3°, 3
0°, 45Hz
30 35 40 45 50 55 60 65 70 75 80 85 90 Q/m3-min1
Fig. 13. 0° and +3° air flow volume Q-efficiency n conversion curve Рис. 13. Кривая преобразования Q-эффективности n объема воздуха при 0° и +3°
Ma Heng, Guo Yao, Liu Xiang. Research and analysis of frequency regulation and operation efficiency
of the main mine ventilator
Ма Хенг, Гу Яо, Лиу Сян. Анализ частотного регулирования и эффективности работы
основного шахтного вентилятора
It can be concluded that under the angle of +3°, the frequency conversion operation of the ventilator has changed from 35 Hz to 40 Hz and then to 45 Hz, and the efficiency curve moves to the upper right. At 0° blade angle, the frequency conversion operation of the ventilator has changed from 50 Hz to 45 Hz and then to 40 Hz, the wind pressure curve moves to the lower left, indicating that the efficiency is gradually reduced from a large frequency to a small frequency under the large blade angle, and the efficiency has gradually increased from a small frequency to a large frequency under a small blade angle.
5. Conclusions
1) Experiments show that air flow Q-efficiency n curves of the same blade angle
have the same trend as the frequencies vary. With an increase in the air flow volume Q, efficiency n first increases gradually, and decreases after the highest efficiency point which varies according to the variation of frequencies. Under the same blade angle, the highest efficiency point increases as the operating frequency increases. The highest efficiency points of the same operating frequency differ under different blade angles, increasing as the blade angle increases.
2) The results show that the pressure curves at a large blade angle with decreasing frequencies would approach to the pressure curves at a small blade angle with increasing frequencies.
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Contribution Критерии авторства
Ma Heng, Guo Yao, Liu Xiang have equal authors' Ма Хенг, Гу Яо, Лиу Сян имеют равные
rights and responsibility for plagiarism. авторские права и несут равную
ответственность за плагиат.
Conflict of interests
The authors declare no conflict of interests.
Information about the authors
Ma Heng,
PhD, Professor,
School of safety science and engineering, Liaoning Technical University, Fuxin, Liaoning, 123000, China; Liaoning Key Laboratory of mine safety, Fuxin, Liaoning, 123000, China, S e-mail: [email protected]
Guo Yao,
School of safety science and engineering, Liaoning Technical University, Fuxin, Liaoning, 123000, China; Liaoning Key Laboratory of mine safety, Fuxin, Liaoning, 123000, China.
Liu Xiang,
School of safety science and engineering, Liaoning Technical University, Fuxin, Liaoning, 123000, China; Liaoning Key Laboratory of mine safety, Fuxin, Liaoning, 123000, China.
Конфликт интересов
Авторы заявляют об отсутствии конфликта интересов.
Сведения об авторах
Ма Хенг,
кандидат технических наук, профессор, Школа безопасности и инжиниринга, Ляонинский технический университет, Фусинь, Ляонин, 123000, Китай; Ляонинская лаборатория исследования безопасности шахт, Фусинь, Ляонин, 123000, Китай, Н e-mail: [email protected] Гу Яо,
Школа безопасности и инжиниринга, Ляонинский технический университет, Фусинь, Ляонин, 123000, Китай; Ляонинская лаборатория исследования безопасности шахт, Фусинь, Ляонин, 123000, Китай. Лиу Сян,
Школа безопасности и инжиниринга, Ляонинский технический университет, Фусинь, Ляонин, 123000, Китай; Ляонинская лаборатория исследования безопасности шахт, Фусинь, Ляонин, 123000, Китай.
