Pharaon Nikolai

                        Justification of operational parameters of a new generation of shearers

In order to analyze the relevance of the topic of applicability of the approximate method of building energy performance for next-generation processor. 

In past generations of shearers used the block diagram of an engine which sets in motion both the executive and the drive mechanism for moving. However, this scheme has had many shortcomings and the main of them - the restriction of engine power due to the overall dimensions of the combine. For this processor has been developed method of calculating the energy characteristics .

In the new generation of combines used a different scheme of work - a separate engine for each executive body of the combine.

The objective of this work is the choice of standard terms and conditions of the shearer, to execute the selected conditions will cut to the approximate scheme of the shearer and the program .

To solve this problem has been chosen method of computer simulation. Using developed at the department of mining machines DonNTU program (which, in turn, has been developed based on common regulations). A calculating and charting package was used in mathematical programming.

На примере комбайна УКД-300 был выполнен расчет по методическим указаниям , расчет по программе и сравнить их результаты.

– Анимация 1. Схема разрушения породного массива проходческим комбайном УКД-300.13.4Кб,кадров 13, количество циклов повторений 50

On the example of the combine OCG-300 was carried out calculations on methodical instructions , the calculation of the program and compare their results.

• To solve this problem have been taken following inputs:
• Resistance to cutting carbon - Аp = 100, 200, 300 кН/м;
• Estimated reservoir thickness - Hp = 1 м;
• Coal grade - Ж, Г, А;
• The diameter of the executive body - Du = 1 м;
• Width - Bs - Вз = 0,63 м;
• The number of cutters on the organ - np = 38;
• Cutting speed - Vр = 3,3 м/мин;
• Efficiency transmission mechanism – ? = 0,8;
• The feed rate Vn = 1, 2, 3, 4, 5, 6 м/мин.

P = ? + b• Vn,

b - The increase in engine power by increasing the feed rate at 1 m / min.

The ratio may be determined by the following formula

where npp- the number of cutters of the executive body while in contact with the slaughter

The coefficients α и β  take into account the grade of coal, are shown in Table1.

Table 1 – - Table of values of the coefficients;α и β .

Значение b в формуле энергетической характеристики определяется по следующему выражению:

где  d – where d - coefficient taking into account the brittle-plastic properties of coal. For viscous coal = 0,95, for brittle = 0,06.

As a result of carried out calculations in the program received a number of computational points.

Estimated value of the angular velocity  w = 6,6.

Carry out an analysis of the calculated capacity of the Program and the calculation of the approximate calculation method with the help of figures - 1, 2, 3.

Figure 1 – The value of a –- the same, and b - are different – различные.

Figure 2 – The value of a –and b - are different.

Figure 3 – The value of a –the same, and b - are different. – различные.

Estimated energy characteristic of the method 1 - dotted line, and the method 2 - solid line. The magnitude and - shows the intercept, and b - the angle of the line. As seen from the graphs, the differences in power are significant. To obtain more accurate values of the discrepancies in the calculations we use for further calculations, some functions of mathematical programming package. As a result, we obtain the values of the coefficients a and b, as well as their percentage difference.

Table 2 - Table of calculated values of the coefficients ? and b by the two methods.

In the process of solving the problem it was found that the difference in the ratio of conditional power "and" up to 600% and increase engine power, ie coefficient "b" up to 46% difference.Therefore, the possibility of using it to evaluate pressures on executive authority on modern machines can be concluded that this technique is not advisable to use.

    Now I am finishing work on building energy characteristics combine new technological level, based on regression models (including cutting and loading)

Therefore, at this moment master is not finished yet.