Steam Pad for iOS

1. Introduction

Steam Pad calculates the thermodynamic and transport properties of water and steam, using the latest releases of IAPWS. It has some distinctive features, and is applicable for industrial, engineering, and teaching processes:

Uses any selected 2 basic parameters to calculate others.

Provides T-S, H-S, P-H, T-H charts, and locates results (point locations) on them.

Computes additional thermodynamic and transport parameters.

Allows saving the results, and supports restoring one of them.

2. Calculator

2.1 Inputs and outputs

By given any selected 2 parameters as the inputs from the Basics (Pressure, Temperature, Enthalpy, Entropy, Specific volume, Vapour Fraction), this App calculates other 4 parameters, and calculates some other thermodynamic and transport parameters. The inputs and outputs of the basics can alternate, which fulfills alterable calculating demands.

2.2 The range of validity

The range of validity defined by pressure and temperature for general properties is the same to the definition in the release of IAPWS IF97.

2.3 Single-Phase regions and Two-Phase region

The calculating demands are handled coordinately both for the Single-Phase regions and the Two-Phase region. The calculated properties and the corresponding region of the results can be distinguished from inputs automatically, and will be displayed in the outputs list box. For example, the saturation properties can be derived from the given P (less than 22.06395Mpa) and X (0.0-1.0).

2.4 Other properties

The optional parameters are calculated based on the releases of IAPWS, or on the physical models, which include:

u: Specific internal energy

Specific isobaric heat capacity

Specific isochoric heat capacity

Speed of sound

Dynamic viscosity

Kinematic viscosity

Thermal conductivity

Entropy index

Static Dielectric Constant

Prandtl number

2.5 Units

The parameters are shown in SI(metric) or in I-P(English) system of units, which can be reset in the Outputs Setting function of the app.

3. Charts

3.1 Chart types

Typical thermodynamic charts are embedded in this app, and displayed as vector-graphs. Only regions 1 to 4 are shown in the charts, and region 5 is ignored for the applicative concern. The gradual changes (the lines) of the other 4 parameters along with the X and Y ordinates, are shown in the charts.

There are 4 charts available:

T-S Chart

H-S Chart

P-H Chart

T-H Chart

3.2 Charts display

The lines of other 4 parameters are displayed in different colors.

Lines are displayed or hidden by checking the checkboxes.

The charts can be moved, enlarged or contracted by dragging or pinching gestures of fingers.

The corresponding values are attached along with the lines at certain intervals.

The boundary of the saturation region, and the critical point, are especially identified.

3.3 Calculated results

The calculated results will be located in the charts as an identifying point (or points) with the corresponding ordinates.

4. Results

The calculated records, each of which contains 6 basic parameters, can be stored in a row in the list of the Results panel by clicking the Save button on the Calculator panel.

The 2 inputs of one record are displayed in a distinctive color.

The region of each result, as well as the possible arrangement number of multiple outputs, is shown on the top of the row.

The records can be re-arranged and be deleted.

The selected record can be restored both on the Calculator panel and on the Charts panel, by clicking the Restore button.