Wärmedurchgang

Heat transition

Transition thermique


Technical description


06/2016 to the programs for Heat Transition For industrial furnaces or freezing techniques,
not suitable for the construction of buildings and central heating.
Stationary = after an "infinitely" long equal heating.
PC-program, operating systems MS-WINDOWS 10, 8, 7 or Vista, 32/64 bit
No schooling, extern software or special hardware requirements are necessary.

The purpose of the Heat transition program is to calculate the heat loss of a kiln wall or of a heat insulation and to find the curve of temperature through the wall of a kiln like shown below, which leads to an optimal construction of different wall rows. If you are in the Homepage and you make a cutting out of the furnace layout, where only the right wall is shown, you get the following diagram.
The X-axis shows the wall thickness and the Y-axis the temperature:

Diagram

Figure 1: Course of temperature through a furnace wall

The furnace wall consists of different rows. The left row at the fire is cast of heavy refractory concrete
(* = neutral to trademarks) 400 mm *Cast 60, which can resist the attack of the flame and the high temperature of 1400 °C. The right row consists of light insulating slabs with the main component calcium-silicate, shorted marked as 50 mm *CaSi 1000. 1000 means that it stands only up to 1000 °C, this row could not resist the internal temperature of 1400 °C. Between them there are placed two rows of refractory insulating brick for different steps of temperature.

Summarized: the (left) inner row shall resist the fire and the (right) outer rows shall cause the insulation. In the following table 1 you see above the dates for the heat transfer between the furnace wall and the ambient air.

Calculation

Table 1: Stationary heat transition calculation

In the middle part of the above table you find the dates from figure 1 and on the right side already further dates. Out of 7 choices is shown the thermal conductivity of the single rows and their weight.

Under the calculation can be put an appertaining material table:

Material table

Table 2: Material table for the calculation According pos. 3 of the price list you can order a file „WLong“ of more than 1500 fireproof and insulating materials. 360 materials are given names neutral to trademarks, like the most heavy materials, e.g. “*B 80, bauxite brick” (* = neutral). Insulating materials are input mostly with trademarks. This material list is divided by 90 multi-lingual headlines, which appear also in the calculation table 1 as a part of the material designation.
From the gratis file with 30 materials is shown the following section:

Material list

Table 3: Material list

For the fireclay brick (above) the short designations following the "Stahl-Eisen-Blatt 910-64" of the "Verein Deutscher Eisenhüttenleute" (Union of German Steel makers) are used. *A35 means, that the brick contains min. 35% Al2O3 (alumna oxide).

Refractory concrete (middle) is usually designed by *CAST or *GUN.

But at the light diatomite brick (below) the designation *MOLER 500 means, that the brick has a density of about 500 kg/m3 = 0.5 kg/dm3 (column 3 ).

The user can at first make a calculation with these designations which are * = neutral to trademarks. Then the suppliers can be selected following commercial points of view. Later material names can be overwritten or materials with trade marks can be inserted in exchange. As the program is organized "self guiding", an intuitive using is possible.
By this the program is fit for calculations with a portable computer at a customer.

Special functions:
Surface: Straight wall, dome, armature, cylinder (also internal cooled)
Temperature depending Thermal conductivity coefficient, also in H2 containing atmosphere,
is shown as parabola in a diagram, it can be extrapolated
and can be inserted into the calculation integral or at middle temperature
To the Thermal conductivity can be inserted a factor and an addition for heat bridges like anchors
Heat Transfer external following ASTM, EN ISO 12241,
VDI 2055 with the formulas: without dimension or at middle temp. wall - air 20°C until 60°C
for wind, sun radiation, constant dates, calm air at roof, bottom or vertical surface
Heat Transfer in vacuum (only radiation)
Heat Transfer internal (hot side) calculated from inner measurements,
emission grade inside, convection, gas radiation of H2O, CO2, CH4,

Comfortable handling:
Numerous info and protections against handling errors
Selection of the material list from the headline list at the screen following
Material-Nº, first name (trademark), main design (e.g. Al2O3%)
A network license can be switched in this way,
that only one workstation has the right to edit in a central material file,
further users can only read the materials at the same time.
Variants can be easily changed and stored

Output:
Calculation with heat-loss/m2 and per m cylinder
with your logo on screen, printer or a file
with weight, estimated price, Heat Capacity in Watt/Joule/kcal/BThU
Dilatation (at a cylinder in 3 directions), dew point for freezing techniques
Formulas for Heat Transition: Radiation and convection extern and intern
Diagram in color for 20 rows max, writing vertical or horizontal.
Under the calculation can be put an appertaining material table
and a text for the limitation of guarantee
From the material list can be exported records to
sequential files readable in clear language

The price of the program can be profitable soon, because the liquidation of a better insulation will be shown, if the cost per m² wall or meter cylinder is compared.

After a download of the DEMO-Version you can call a list of central european suppliers with: Start/Programme/WDurch-Heat Transition/Suppliers of material.
This DEMO-version contains extensions also, which are briefly described in the price-list.
Further descriptions see Info-fastening (in case of order) and target oriented Help in English and German in the program with F1.



The heating or cooling of objects can be calculated, it can be demonstrated in a mathematical model, simplified as multi-layer plate, cylinder or sphere.

In the following example the Heating of a steel ladle will be simulated, which has already been dried.

At first a time schedule must be inserted:
Grafik
Table 4: Time schedule

According to the above time steps 1-8 the following temperature curves are calculated:
Grafik
Figure 2: Temperature curves over the wall thickness

rows on the X-axis of the above diagram:
A)200 mm Cast 30 Zr, refractory concrete
B) 64 mm ASTM C155-70 Gr.28, refractory insul.brick
C) 6 mm BLANKET 1260 °C/130 kg/m3, refractory felt
D) 10 mm SHELL

The heat walks from the inside (left) to the outside (right).

For the same heating process another depiction is selected below:

Grafik
Figure 3: Temperature curves over the time [h]

The above curves show [°C]:
1. Ambient temperature inside
2. Surface temperature inside
3. Surface temperature outside
4. Border temp. between layers 1 and 2

The sudden rise of temperature is caused by "Fill in liquid steel" (table 4, time step 7)

This instationary programme is developed by an mathematician and somewhat more complicated.
Therefore no DEMO-version is prepared for a download.
It is an additional programme to the above under A. described stationary programme.
Also to this instationary programme extensions are briefly described in the price list.