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3.1 Analysis of results of calculation of a regular heater

In the given chapter results of numerical research of a current of air in system of ventilation and car heating are reduced. At holding of researches in the varied parametre speed and intensity of turbulence on input boundary (an operating mode of a supercharger) are.

Calculation was spent for a heating condition (all stream is directed through a heat sink), for three values of speed Ui = 2,51 km/s; U2 = 3,75 km/s; from = 4,51 km/s.

The comparative analysis of influence of boundary conditions on structure and stream parametres allows to mark the following.

After an input all stream goes on a heat sink that leads to stream turn. Therefore the stream structure is characterised by obviously expressed non-uniformity at a heat sink flow that proves to be true field of vectorses of speeds, on all operating modes of a supercharger (rice 3.1). After transiting of a heat sink the current structure is aligned, but thus there is a lowering of the module of speed about 3 km/s to 1,5 km/s.

On fig. 3.2 to an input, before a heat sink, on a heat sink and after it distribution of full pressure is presented to planes of symmetry of heat sink XOZ for three operating modes of a turbine supercharger.

Among the requirements shown to a heat sink - security of necessary aerodynamic resistance. On fig. 3.3, 3.4 results of calculation of pressure difference on a heat sink depending on speed of air arriving in a heater (an operating mode of a turbine supercharger) are presented. Apparently from the graph on fig. 3.4, settlement data of aerodynamic resistance do not exceed requirements shown to automobile heat sinks ARr < ДРТ.

Natural alignment of a velocity profile after heat sink transiting is displayed on fig. 3.5. Apparently from fig. 3.5 after a heat sink there is a division of a stream into rather equal parts. Approximately half of stream goes to the lower part of the case (on deflektory, giving air in feet), other part is directed on nozzles of a dusting of a windscreen, and as central and side deflektory to the panel of gears.

Fig. 3.1 Structure of a stream on an input in a heater, before a heat sink, a heat sink and after a heat sink, at speeds of a stream on an input (intensity of turbulence is equaled 10 %): a) U | = 2,51m/with;) и2 = 3,75 km/s;

ui = 4,51 km/s

Calculations have displayed, that in 3.6 areas specified in fig. are organised otryvnye zones. The analysis has displayed, that irrespective of magnitude of speed and intensity of turbulence on an input,

The amount, arrangement and the sizes otryvnyh zones do not undergo considerable change (fig. 3.7).

/

Fig. 3.2 Field of full pressure before a heat sink, on a heat sink and after it in section on plane of symmetry XOZ (intensity of turbulence is equaled 10 %): a) U | ~ 2,51 km/s;) и2 = 3,75 km/s;

и3 = 4,51 km/s IIJ4

DR = 89.5 Pases a = 461.097 kg/m3 R = 4.452 kg/m4

Я1Л11Л Met

Itl*.

ML 1СХМ № (WASP MO »UV

FIG. 3.3 Pressure difference on a heat sink for the second operating mode of a turbine supercharger (intensity of turbulence is equaled 10 %)

160

I

WITH 140

X 120

z

j 100

5 80

5 60 it

WITH 40

g "20 with

0

I II III

Heater operating mode tralnoj heater parts vi

Ri

«>

Mi im

im

in*

in

Ml UN

THE CENTRAL PROCESSING UNIT »r

Value

Fig. 3.4 Pressure difference on a heat sink depending on a heater operating mode (I = 0,1): ARr - the calculated pressure, DRt - demanded

Zones of a tear of a stream

With. j.j gshdelenni a note

The arrangement and the sizes otryvnyh areas give the information on importation of corrective amendments in the shape of a cross-section of airlines for the purpose of reduction of losses of pressure on their length. Results of calculation of losses of pressure on various airlines depending on an operating mode of a supercharger are presented on fig. 3.8.

Fig. of 3.6 Zones of a tear in the lower part of a heater with sections on planes XOY and XOZ in three operating modes of a heater (intensity of turbulence is equaled 10 %): a) Ui - 2,51m/with;) lb = 3,75 km/s;

Mpgjk " VMtmmi

YEAR »

Uj - 4,51 km/s S §

About 2 3 2 and

About I

"-tr

About

p

45 40 35

30 25 20 15 10 5 0

Heater operating mode

Fig. of 3.7 Size otryvnoj zones depending on an operating mode of a supercharger (intensity of turbulence is equaled 10 %) oll

Operating mode

Fig. 3.8 potern pressure in heater paths (I = 0,1): DRl to th left deflektore; DR „- on right deflektore; DR„ to th central deflektore; DR „„ - on central lower deflektore; DR, „, - on left lower deflektore; DRPI - on the right lower deflektore

One of the most important, from the practical point of view, results of calculation spatial distribution of speeds of air in output sections deflektorov systems of heating of the car is. 3.9 spatial velocity profiles presented on fig. in deflektorah a windscreen dusting display obviously expressed non-uniformity. Integral values of speeds in output sections depending on an operating mode of a supercharger are presented to tab. 3.1

For an estimation of non-uniformity of distribution of a velocity profile the factor of non-uniformity of speed is entered into planes of symmetry of output sections left and right deflektorov a windshield dusting X = Vmax/Vcp. For right deflektora the non-uniformity factor on different operating modes of a heater makes magnitude Xi = 2,89; Xi\= 2,94; Xjii = 2,92; for left ~/j - 3,46; the Chi - 3,45; yjw - 3,46. The received results allow to draw a qualitative output on slower thawing

Windshield during the winter period on the car from the driver that aggravates visibility and negatively influences passive safety at a driving which is regulated by requirements of standard S-103. This qualitative output results of distribution of a kinetic energy of turbulence and speed of a dissipation of a kinetic energy in output sections left and right deflektorov a windscreen dusting (confirm fig. 3.10, 3.11), calculated for three operating modes of a supercharger with intensity of turbulence on an input, accordingly, 5 %, 10 % and 15 %.

Table 3.1 - Value of speed on an exit from deflektorov the Operating mode of system of heating and ventilation Speed of air on an exit from deflektorov,

Km/s Productivity of system of heating and ventilation, in feet in the panel of gears of waters. A pass. A lion. Cent, a lion. Cent, the rights. The rights. I 3,25 2,40 2,06 1,83 1,83 2,12 200 II 3,76 2,84 3,07 2,56 2,56 2,84 300 III 4,77 4,21 3,7 3,05 3,05 3,29 365 change of a kinetic energy of turbulence and speed of a dissipation on length of a path of a heater is examined. Results are presented on fig. 3.12, 3.13. As distribution of a kinetic energy of turbulence to and speeds of a dissipation of a kinetic energy e on the heater case not homogeneously follows from introduced results. On an input value of a kinetic energy of turbulence and speed of its dissipation makes к=0,486 m2/s2 and е=20,93 m2/s3,

1 »jutchooich/• practically

giso.sh gasprede.tenie kineticheskoi energy turoulentnosti in deflektorah a windscreen dusting: the first operating mode (I = 0,05); the second operating mode (I = 0,1); the third operating mode (I = 0,15)

Right deflektor

Left deflektor

IN

Fig. 3.11 Distribution of speed of a dissipation of a kinetic energy of turbulence in deflektorah a windscreen dusting: the first operating mode (I = 0,05); the second operating mode (I = 0,1); the third operating mode (I = 0,15)

It is glad. It is glad.

Fig. of 3.12 Distributions of a kinetic energy of turbulence on a heater

To, m2/s2

e, m2/s3 N2 (93 G \L/.12 I / V, 83 G / / V ' JZ. / the Input before the ambassador an exit

It is glad. It is glad.

R

не.3.13 Distributions of speed of a dissipation of a kinetic energy on a heater

On the basis of the analysis of results of numerical calculations it is possible to mark the following.

1. In the lower part of a heater circulating zones of an air stream, thus small diffusers in sizes are organised ensure sufficient speed on exits, but they are located in such a manner that

Does not allow them in sufficient measure to ventilate space in a zone of feet of the driver and the forward passenger. Therefore the geometry and an arrangement deflektorov directing a stream in the lower part of salon require finishing.

It is recommended to change a heat sink arrangement (vertical on horizontal) that will allow to arrange more uniformly an air stream before a heat sink (will raise teplootdachu a heat sink), to benefit in space for arranging of the evaporator and more uniformly to arrange an air stream after a heat sink.

For heightening of efficiency of a dusting of a windscreen and uniformity security (conditions of a dusting of glass are extremely non-uniform % ~ 2,9; % ~ 3,5) distributions of a stream of air through flat (slotted) mounting attachments of an airline, it is necessary to change a construction of the central airline of system of heating.

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A source: Matveev Denis Viktorovich. WORKING out of TECHNIQUE of CALCULATION of SYSTEM of HEATING And CAR VENTILATION. The thesis on competition of a scientific degree of a Cand.Tech.Sci. Izhevsk - 2006. 2006

More on topic 3.1 Analysis of results of calculation of a regular heater:

  1. 3.2 Analysis of results of calculation of a modernised construction of a heater
  2. CHAPTER 3. NUMERICAL REALIZATION OF THE MATHEMATICAL MODEL AND THE ANALYSIS OF RESULTS OF CALCULATION OF NON-UNIFORM PHYSICALLY NONLINEAR THIN-WALL SPATIAL DESIGNS
  3. CHAPTER 4. NUMERICAL REALIZATION OF THE MATHEMATICAL MODEL AND THE ANALYSIS OF RESULTS OF CALCULATION OF PHYSICALLY NONLINEAR THIN-WALL SPATIAL DESIGNS OF THE VARIABLE THICKNESS
  4. casual and regular errors of selection of frequencies in eksperimenyotalnye spectrums. Calculation harmonious and angarmonicheskih frequencies. RegresYOsionnye dependences «experimental frequencies-theoretical of frequency»
  5. 3.2. Results of bench tests of calculation of heat
  6. Calculation of reliability of the gained results
  7. Calculation of reliability of the gained results
  8. 3.3. Calculation and the analysis of indicators of efficiency of investments
  9. 4.2. Calculation of an integrated indicator as element of the factorial analysis.
  10. the comparative analysis of the gained results of the developed system of machining and the analysis spektrozonalnyh images
  11. 1.1.1.1 Theory of a regular polysemy of J.D.Apresjana
  12. Comparison of the given experimental researches to results of the settlement analysis
  13. the Collecting and the analysis of own results
  14. methods of the scientific analysis and statistical processing of the received results
  15. the Early analysis of own results
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