Currently the development of new machine designs and methods of their engineering calculation is one of the most priority areas of construction industry. It allows one to carry out research at the stage of theoretical calculations in order to predict the expected result. One of the promising constructive solutions for economic profitability increase of mixing equipment is the use of deformable working chamber

Kostina, I. В.

Logvinova, L. V.

Lozovaya, S. Y.

Satler, O. N.

Ziborova, E. I.

DSpace at Belgorod State University

IOP Conf. Series: Journal of Physics: Conf. Series1118 (2018) 012024 doi:10.1088/1742-6596/1118/1/012024International Conference "Complex equipment of quality control laboratories" IOP PublishingExperimental studies of energy characteristics of mixer with deformable cameraS Yu Lozovaya1, N M Lozovoy1, L V Ryadinskaya1, I В Kostina2, О N Satler2, L V Logvinova2 and E I Ziborova21 Belgorod State Technological University named after V. G. Shukhov, 46, Kostyukov str., Belgorod, 308012, Russia2 Belgorod National Research University, 85, Pobed str., Belgorod, 308015, Russia E-mail: lozwa@mail.ruAbstract. Currently the development of new machine designs and methods of their engineering calculation is one of the most priority areas of construction industry. It allows one to carry out research at the stage of theoretical calculations in order to predict the expected result. One of the promising constructive solutions for economic profitability increase of mixing equipment is the use of deformable working chambers. The main feature of such working chamber is the ability to change its overall dimensions during its deformation, which allows obtaining a new mechanism of influence on the processed medium, using it as a working element. Thus, the main output parameter for any deformable working elements is the movement transferred to the particles of the materials being mixed. Output parameters that have a small effect on the value of particle displacement are the characteristics of the chamber such as the material (stiffness, elasticity in the presence of cording) and execution (shape, installation method, various design decisions). Various types of rubber can be used as the material for chamber making that depends on the required mixing conditions such as the degree, type and intensity of the chamber defonnations, as well as the required quality of the final product. Simplicity of introducing mixers into existing technological lines should also be noted. That increases the economic efficiency for both large and small enterprises, focused on making a profit at minimal cost.1. IntroductionEvaluation o f the equipment use efficiency in relation to a specific technological process and to the processed materials requires experimental studies to determine the main technological and operational characteristics o f the devices under study. At the first stage it is necessary to conduct evaluation tests with various combinations o f parameters, to compare theoretical and experimental data and to determine the main factors that influence the process o f material mixing and to choose the intervals for their variation. The second stage assumes experimental research with application o f multifactorial planning. The results processing involves the use of a comprehensive research method [1], including system analysis; mathematical, physical modeling; methods o f mathematical statistics and the use o f computer engineering.2. Experimental studiesIn the devices being developed, the quality o f the mixing process depends on the frequency o f the effect on the elementary volumes o f the components being mixed per unit time:Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.Published under licence by IOP Publishing Ltd 1I OP Conf. Series: Journal of Physics: Conf. Series 1118 (2018) 012024 doi :10.1088/1742-6596/1118/1/012024International Conference "Complex equipment of quality control laboratories" IOP Publishing- under cramped conditions -  on the intensity o f the shell walls impact on the mixture;- under free conditions -  on the intensity o f the shell walls impact on the mixture and on the freespace volume in the working chamber [2].The raise o f the rolling castors force impact on the deformable chamber increases the intensity o f the particles relocation in the material being mixed that can be achieved by external and internal forces (for example, using a corrugated body) [3].The deformable working chamber in question has a cylindrical shape and is installed horizontally (under a slight inclination to 8°), while the body o f the working chamber is rigidly fixed to the trunnions (Figure 1). The outer part of the body is tightly enfolded in the cross section by the clamps, which are spherical bodies rigidly fixed on the axis. The axis o f the clamps, in turn, is installed in the support bearings. From the drive shaft, rotation is transmitted to the clamps. Rolling the body of the working chamber from the outside, they deform it periodically (with the frequency of the shaft rotation), thereby causing the mixing material to move. The efficiency of the material mixing process can be increased by raising the clamps rotation speed.Figure 1. Diagram o f cylindrical working chamber:1 - clamps; 2 - supporting bearings; 3 - deformable cylindrical working chamber; 4 - pin; 5 -  carrier.Planning an experiment using mathematical methods makes researcher's work more ordered and generally increases its effectiveness. In order to obtain reliable results at each stage o f the research, it isnecessary to measure the results under identical conditions and with constant parameters and modes ofmaterial mixing [4].Twelve experiments have been preliminary conducted at constant modes of material mixing. By the ratio KL,d KVlU= 1.23 for the mixing process with the reliability o f the experimental results o f 0.95, we set the required number o f repetitions of each experiment equal to 3. The central composite rotational plan o f the complete factor experiment is chosen as the main experiment design.The polynomial of the second degree has the form:3 3 3 3У = H auxu + H a> xf +i=0 i= j= 2 /=1 (1)where a,, a, - estimation of regression coefficients;Xu Xj - planning factors and their combinations; e - experiment error;у - observed response of functional dependence.2I OP Conf. Series: Journal of Physics: Conf. Series 1118 (2018) 012024 doi :10.1088/1742-6596/1118/1/012024International Conference "Complex equipment of quality control laboratories" IOP PublishingThe energy parameters in devices with deformable working chambers are affected by a sufficiently large number of factors:P = f(n ,L ,D ,K ,K 3 A , t ) ,  (2)where n -  rotational speed o f the drive;D - working area diameter before deformation;К - % mixture components ratio;K, - load density;L -  length of the working area;Л - deformation coefficient of the working area; t - time o f material processing.The mathematical model o f the process is the function connecting the optimization parameter P  (the power consumed by material mixing) with variable factors (Table 2).To simplify the mathematical planning o f the experiments and to reduce the number o f variable factors, it was found experimentally that the mixing process proceeds the more intensively, the greater the deformation coefficient o f the grinding chamber is, but the maximum possible deformation o f the body should not exceed 25% of the original chamber size. Otherwise, loss of its stability is observed[5].The load density К  is assumed to be maximum (the chamber is filled with material after deformation), since it ensures maximum performance. Cylindrical chambers with volume V = 3 l were used for the experiments (radius (R) was equal to 0.05 m and length (L) was equal to 0.2 m). The mixing time was assumed to be 7 minutes, as the best one for obtaining the required quality mixture for the proposed levels o f the selected factors variation (Table 1).The factor o f changing chamber filling by material, similarly to the existing mixers, was equal to 0.75% (2.5 L) of the chamber volume (3 L). There is a problem of mixing the basic components of dry building mixtures with different physical and mechanical characteristics, and the mixing device is fundamentally new. So under the proposed conditions, for determining the working capacity o f the device, sand was selected as the basic material with particle sizes o f 1.25-2.5 mm; cement brand was 350. The ratio of mixture components varied within 90/10 -60/40%.According to the evaluation tests, the mixing time is 3 min, the drive speed is 100 to 300 rpm (pivot rotation frequency is 10.5 to 31.5 s-1), because less than 100 revolutions during a short mixing time led to the inhomogeneity factor of 60% and during 180 rpm during the maximum mixing time o f 7 min, the inhomogeneity factor was 75.7%, which can be explained by the fact that the cement particle, compared to the sand particles, has a higher dispersion and under the action o f centrifugal forces, sand particles are thrown to the chamber walls (separation into factions), conducing increase of mixture heterogeneity ratio.Models have combinations o f priority arguments that affect the process management o f reducing the energy characteristics o f mixing devices that can be used for research. To check the correctness of the mathematical models obtained, the following technological parameters were selected (Table 1).3I OP Conf. Series: Journal of Physics: Conf. Series 1118 (2018) 012024 doi :10.1088/1742-6596/1118/1/012024International Conference "Complex equipment of quality control laboratories" IOP PublishingTable 1. Intervals and levels o f independent variables variation.independent variablesVariation levelsBasicVariation intervalsUpper level Lower levelUpper star point Lower star pointn, rpm K, % Mixture components ratioNatural Coded Natural „ , , ,, Coded fonn fonnfonn form75/25400 0 (1225kg/m3)0100 - 11/9 (45 kg/m3)66/34-500 +1 (1270kg/m3)84/16+1300 -1 (1180kg/m3)60/40-1650 1.682 (1300kg/m3)90/101.682150 -1.682 (1150kg/m3)-1.682Figure 2. Grid o f experimental studies o f change in mixer power.Based on the results o f the experimental data (Table 2), the regression equations in the coded (3) and decoded (4) forms and their graphic interpretation (Figure 2) are obtained for cylindrical chambers:4I OP Conf. Series: Journal of Physics: Conf. Series 1118 (2018) 012024 doi :10.1088/1742-6596/1118/1/012024P=34.8+9.6xi-3.9x2-xiX2+37.3xi2+34.3x22', (3)P=1449-3n-l 71 К  -0.005n К  +0.004n2+9 K2. (4)The importance o f factors for cylindrical chambers is «=72%, К  =28%.International Conference "Complex equipment of quality control laboratories" IOP PublishingTable 2. Experimental resultsXi x 2 Xj2 x 22 XjX2 Y  av, W Y c a lc ,  W %1 -1 -1 1 1 1 115 102.35 112 1 -1 1 1 -1 140 121.80 133 -1 1 1 1 -1 109 99.19 94 1 1 1 1 1 126 110.88 125 -1.682 0 2.829 0 0 117 108.81 76 1.682 0 2.829 0 0 170 146.20 147 0 -1.682 0 2.829 0 145 136.30 68 0 1.682 0 2.829 0 125 113.75 99 0 0 0 0 0 40 38.00 53. Results and discussionThe results o f the experiment have shown that the most significant factors in the process o f reducing the energy characteristics of a mixing device with a deformable chamber is the rotational speed o f the drive. The dependence o f the objective function on the weight or percentage ratio o f the components o f the mixture and the speed o f the drive has the form of a parabola, which indicates the presence of the largest or smallest values for this function, i.e. we can talk about the existence o f an optimal size of the investigated factors. The analysis o f the graph (Figure 2) has shown that the power P = 30 W is achieved with the ratios o f the mixture components varying in the range 90/10 (1150 kg/m3) - 75/25 (1225 kg/m3) and the drive speed o f approximately 300 rpm that corresponds with theoretical investigations. It can also be seen that the minimum power value P  = 18 W  in the mixing device under consideration is achieved by varying the factors K=  84/16% (1180 kg/m3), n = 300 rpm. It is established that for mixing devices with a cylindrical chamber, when using in the materials being mixed, the percentage ratio o f the considered factors is К  = 66/34% (1270 kg/m3), a sharp increase in power values (8-15 times) is observed. Limitation of the weight values range or of the percentage ratios o f the mixture components is explained by their close correspondence with the coefficient o f chamber filling. Increasing the ratio o f the components o f the blended material reduces the distributability o f the component with a small percentage, which requires a longer mixing time, and this leads to an increase in energy consumption.The results o f experimental studies of power variation for mixing devices with a deformable working chamber o f a cylindrical shape confirm the data obtained theoretically. From the analysis it can be concluded that the selected factors influence the process o f lowering the energy characteristics o f the device under consideration, and the obtained dependencies allow determining the output parameters for any combination o f arguments, thereby predicting the results of the process under study.References[1] Braginsky Ln, Bogachev V I and Barabash V M 2009 Mixing in liquid media The physical principles and engineering methods o f calculating Chemistry (Moscow: Chemistry) 336[2] Vasiltsov V A and Ushakov V G 2011 Apparatus for mixing liquid media (Mechanical Engineering) 271[3] Eremin N F 1986 Processes and apparatus in the technology o f building materials (Moscow: Higher Education) 736[4] Uvarov V A and Lozovoy N M 2012 Determination o f forces in a mixer with a variable working chamber o f periodic action (Vestnik Belgorod State Technological University named after V G Shukhov 1) 56-59[5] Lozovaya S Yu, Lozovoy N M, Peshkov О V and Ryadinskaya L V 2017 Theoretical basis for  calculating the energy characteristics o f  a mixer with a deformable chamber o f cylindrical shape (Fundamental research 10) 245-2505

Experimental studies of energy characteristics of mixer with deformable camera

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Experimental studies of energy characteristics of mixer with deformable camera

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