GB/T 10294-2008Thermal insulation -- Determination of steady-state thermal resistance and related properties -- Guarded hot plate apparatus (English PDF)

0.1 Standard Architecture

This standard is divided into three chapters, describes the use and design of all the information guarded hot plate apparatus need.

1 Overview;

2 devices and error analysis;

3 during the test.

In terms of the test operator for the purpose of Chapter 3 may notice only, but in order to get accurate results, the operator also needs to be familiar with the other two chapters, He must outline a more profound understanding. Chapter 2 direct means for the designer, but in order to create a good means he wants to focus on its His two chapters. Thus, the standard method will better achieve their goals.

0.2 Properties of Heat Transfer and Measurement

Most of the heat transfer properties of the test is for the low density of the porous material. In this case, the material inside pass real passion to obtain accurate results, this standard only for design and operation of guarded hot plate apparatus made necessary mandatory.

Appendix A lists the limit values \u200b\u200bof the standard set forth in the performance of the device and test conditions.

The specimen size standard also contains the recommended procedures and practical knowledge, as well as recommendations, which will raise the general level of measurement help to improve inter-laboratory comparison measurement procedures and cooperation.

GB/T 10294-2008/ISO 8302:1991 Determination of steady-state thermal insulation materials and related properties Guarded hot plate

1.1 Scope

This standard specifies the calculation using the guarded hot plate apparatus measures the plate-like specimen steady heat transfer properties and methods of heat transfer properties.

The present method is to measure the heat transfer properties of the absolute law or arbitration law, only need to measure the size, temperature, and electrical power.

The standard test methods in line with the report of the test piece the thermal resistance not less than 0.1m2 · K/W, and a thickness of no more than the requirements of 1.7.4.

Specimen thermal resistance limit can be as low 0.02m2 · K/W, but not necessarily to achieve accuracy 1.5.3 according to the full extent.

If the specimen only to meet the requirements of 1.8.1, the test results indicate the thermal conductivity and thermal transfer coefficients or specimen.

If the specimen meet the requirements of 1.8.2, the test results can be expressed by the average of the test piece can be measured thermal conductivity.

If the specimen meet the requirements of 1.8.3, the test results may indicate an apparent thermal conductivity or thermal conductivity of the material being tested.

1.2 Normative references

The following documents contain provisions which, through reference in this standard and become the standard terms. For dated references, subsequent Amendments (not including errata content) or revisions do not apply to this standard, however, encourage the parties to the agreement are based on research Whether the latest versions of these documents. For undated reference documents, the latest versions apply to this standard.

ISO 7345. 1987 Adiabatic --- Physical quantities and definitions ISO 9229:1991 --- insulation materials, products and systems --- Vocabulary ISO 9251. 1987 adiabatic heat transfer conditions and material properties --- --- Vocabulary ISO 9288. 1989 radiation heat transfer insulation --- --- Physical quantities and definitions ISO 9346. 1987 MASS insulation --- --- Physical quantities and definitions

1.3 Terms, definitions, symbols and units

ISO 7345 or ISO 9251, and established the following terms and definitions apply to this standard.

Physical symbol Unit Heat flow Phi W Heat flux q W/m2 Thermal Resistance 1) R m2 · K/W Thermal conductivity Lambda W/(m2 · K) Thermal conductivity 2) lambda W/(m · K) Thermal coefficient gamma m · K/W Porosity xi Local porosity xip

1) In some cases, you may want to consider is the temperature difference between the heat flow in addition, no special symbols to represent the physical, sometimes also called resistance.

2) In most cases, the direction and q -> gradT different (lambda not determined by a single constant lambda, but by the constant matrix). In addition, the specimen inside Position changes, temperature changes and time changes will lead to changes in the thermal conductivity.

Porous body porousmedium Homogeneous body homogeneousmedium Homogeneous porous body homogeneousporousmedium GB/T 10294-2008/ISO 8302:1991