Improving the efficiency of the grain harvester's straw grinder due to additional effects on the processed mass

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INTRODUCTION
The use of such material as straw can help reduce the amount of fertilizer used, it allows reducing the costs of purchasing and using mineral fertilizers, and also improves the humus composition of the soil [1, 2, 3].
An integral part of many technological processes performed by agricultural machines is compression deformation [4]. Compression of stems, branches, shoots and other materials can be in the transverse and longitudinal directions. Compression in the longitudinal direction can lead to loss of stability (longitudinal bending), and most plant materials cannot withstand it due to their low rigidity.
Compression in the transverse direction in the absence of restrictions and in their presence was studied on the stems of flax, wheat, rye and kenaf, and under the action of forces in mutually perpendicular directions - on models (it was compared with compression in the absence of restrictions). Compression of the stem by forces acting along the entire perimeter has not been studied at all. In some plant materials (hay, straw), transverse compression does not lead to negative consequences, while in others (flax stems, seeds, fruits, berries) it can lead to undesirable consequences (lower yield of long flax fiber, spoilage of seeds, fruits, berries, etc.). It should be noted that the term "compression" of the stem means compression of its tube (i.e. its flattening), during which the stem material bends in the longitudinal and transverse directions [5, 6]. RESEARCH METHODS
Transverse compression can occur both in small and large sections compared to the length of the stem. In the process of processing plants, cases of compression of previously cut parts of the stems are also possible. Below, the patterns of compression of individual sections of the stems are considered, with compression in the absence of restrictions on both sides of the line of action of forces first analyzed. Special devices have been developed for studying transverse compression. For this purpose, an extensometer with a special device can also be used [7].
With a further increase in load, the deformation grows even faster, and the stem begins to flatten.
With transverse compression of the stem with restrictions on both sides of the line of action of the forces, the resistance to compression increases. The nature of the deformation of the plant under such loading depends on the variety and condition of the crop. This process is also influenced by factors such as pressure, area of ​​the deformer, thickness of the tube wall, etc.

The deformation process of freshly harvested stems consists of a number of phases. First, under the action of pressure, the circumference of the stem takes a shape close to a rectangle, then the side walls of the tube are deformed due to their loss of stability and the stem is flattened [8].
The deformation process of dry stems also consists of a number of phases. First, cracks, breaks and bends appear on the stems, and then the stems are completely flattened with the formation of a significant number of cracks and breaks.
A study of the compression process of dry stems in the presence of lateral restrictions established a pattern of changes in linear deformation depending on pressure, which is largely similar to the pattern for freshly harvested stems, but there are also some differences due to the fragility of dry stems [9, 10].
It should be noted that the closure of the inner walls of the stem tubes and the deformation of their soft parts, after which the wood of the stem, characterized by high resistance to compression, begins to deform. RESULTS OF THE STUDY AND THEIR DISCUSSION
The studies were carried out on the assembled setup (Fig. 1), barley straw was used for the experiment.

1 – setup body, 2 – setup support, 3 – straw container, 4 – pressure plate, 5 – guide, 6 – direction pin, 7 – load rod, 8 – load.

Fig. 1. Diagram of the laboratory setup.
Fig. 1. Diagram of the laboratory setup.

The experiment involved studying the compaction of straw under the influence of certain forces.
Repeated compression of the stems can take place with the same stroke of the piston or with different strokes, with the same force or with different forces; in addition, the same stems can be repeatedly compressed, or the same stems, but with the addition of a new portion of stems before each repeated compression.
The simplest case is the compression of one group of stems with the same force without adding a new portion.
The experimental study of the compression of stems in the plane was carried out as follows.
Dry barley stems (Fig. 2b, 2c) were placed in a laboratory setup for compressing stems (Fig. 2a), then they were subjected to the action of a constant force (Fig. 2d), and the compaction value (Fig. 2d) was measured after each impact of the load on the straw.

Fig. 2.a. Laboratory setup. Fig. 2.b. Container for laying straw.
Fig. 2.a. Laboratory installation. Fig. 2.b. Container for laying straw.

Fig. 2.c. Laying the stems. Fig. 2.g. The effect of the initial force.

Fig. 2.d. Measurement of the seal.

To determine the force of the load's mass on the straw, we will use the following formulas:
Load's force of impact:

(1)

Load acceleration over a period of time:

(2)

Load's speed:

(3)
Impact time:
(4)
where h is the distance from the load to the crushing plate;
m is the mass of the load (0.7 kg).

To determine the energy consumption (E), we will use the formula:

(5)

The data obtained for the barley stalks are presented in the table.

Table Compression of stems under repeated loads
Table Compression of stems under repeated loads

Experimental options	Number of cargo drops in order	1	2	3	4	5	6	Fпл, Н	E, Дж
1	Load drop height, m	0,7
	Straw layer thickness, mm	70	20	15	14	12	10	7,21	4,81
2	Load drop height, m	0,6
	Straw layer thickness, mm	70	24	18	16	14	13	6,86	4,12
3	Load drop height, m	0,5
	Straw layer thickness, mm	70	29	22	20	18	16	6,81	3,43
4	Load drop height, m	0,4
	Straw layer thickness, mm	70	33	25	23	20	17	6,76	2,75
5	Load drop height, m	0,3
	Straw layer thickness, mm	70	37	28	26	23	21	6,68	2,06

In the experiments, each subsequent load is applied after the deformations cease (and the subsequent load is equal to the previous one).
After the experiments, graphs of the first and last experiments were constructed, which displayed the largest and smallest force of action on the straw (Fig. 3) of the change in the thickness of the straw layer from the number of repetitions of compression and the effect of a certain force.

Fig. 3. The change in the thickness of the straw layer from the number of repetitive loads.

It was established from the graph that the total deformation of the stems will increase with the growth of load cycles. As a result, the total deformation of a group of stems tends to a certain limit of compaction, at which the stems acquire an elastically compacted state.
Experiments conducted at different values ​​of force with dry barley stems showed that the limit of compaction occurs after 7 ... 11 cycles. By assessing the degree of compression of straw (Fig. 4), it was found that to compact 71% of dry straw, it is sufficient to apply a load once.

Fig. 4. The degree of compression of the straw.
Fig. 4. The degree of compression of the straw.

It should be noted that after the closure of the inner walls of the stems and the deformation of their soft parts, the stem material begins to deform, which is characterized by high resistance to compression.
When analyzing the obtained graphs, a pattern of straw compression was established, presented in the form of two graphs. One graph (Fig. 3) is plotted in the coordinates "number of loads - straw layer thickness", i.e. the number of subsequent loads with the same force is plotted along the abscissa axis, and the compression of materials in millimeters is plotted along the ordinate axis. The other graph (Fig. 4) is plotted in the coordinates "number of loads - compression ratio", i.e. the number of subsequent loads with the same force is plotted along the abscissa axis, and the compression ratio in percent is plotted along the ordinate axis.
It can be noted that with an increase in the number of subsequent loads, the compression ratio of the straw increases, but for use in a combine harvester, a single load is sufficient for the degree of straw crushing to reach 70%. It is worth noting that not much force is needed to flatten dry straw, which means that the energy consumption for the flattening mechanism will be small - about 5 J.
CONCLUSIONS
Based on the results of the studies, it can be judged that the force required for flattening is insignificant. At the same time, with an increase in the force of impact on the straw, its degree of flattening increases.
The use of straw flattening allows to accelerate its decomposition by 5.2%, and the level of flattening of 70% of the straw is achieved by a single impact of a force, the energy of which is equal to 4.81 J. This allows to increase the efficiency of harvesting, while slightly increasing the energy consumption for straw flattening.

About the authors

Oleg V. Gordeenko

Educational institution "Belarusian State Order of the October Revolution and the Red Banner of Labor Agricultural Academy"

Email: sxm@baa.by
ORCID iD: 0009-0006-6229-9396
SPIN-code: 4845-7178

доцент, канд. техн. наук,

зав. кафедрой «Сельскохозяйственных машин»

Belarus, 2134105, Belarus, Mogilev region, Gorki city, Michurina street, 5

Stepan I. Kozlov

Educational institution "Belarusian State Order of the October Revolution and the Red Banner of Labor Agricultural Academy"

Email: Stepan-61@mail.ru
ORCID iD: 0000-0003-0128-3455
SPIN-code: 4731-8381

Associate Professor, Candidate of Technical Sciences, Associate Professor of the Department of Animal Husbandry Mechanization and Electrification of Agricultural Production

Belarus, 2134105, Belarus, Mogilev region, Gorki city, Michurina str., 5

Vasily M. Kuzyur

Federal State Budget Educational Institution of Higher Education “Bryansk State Agrarian University”

Email: kvming@mail.com
ORCID iD: 0009-0002-0232-6680
SPIN-code: 4505-9405

Candidate of Technical Sciences, Associate Professor of the Department of Technical Service

Russian Federation, 243365, Russian Federation, Bryansk region, Vygonichi district, s. Kokino, Sovetskaya str., 2a

Sergei I. Budko

Federal State Budget Educational Institution of Higher Education “Bryansk State Agrarian University”

Author for correspondence.
Email: s.budko.32@bk.ru
ORCID iD: 0000-0002-1291-4235
SPIN-code: 7502-3169

кандидат технических наук, доцент кафедры технического сервиса

Russian Federation, 243365, Russian Federation, Bryansk region, Vygonichi district, s. Kokino, Sovetskaya str., 2a

References

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