Laboratory
Thermodynamics and Fluid Dynamics Engineering (LWS)
Sketch by Leonardo da Vinci
The theoretical lectures in metrology, thermodynamics and fluid dynamics are accompanied by demonstrations of various experiments and equipment and the following laboratories are offered in the LWS laboratory:
Thermodynamics
Hydrokinetic flow machines
Metrology
The laboratory supervises and supports final projects for the Bachelor degree and the project work 1 and 2 which thematically match the range of tasks undertaken by the laboratory. Besides fulfilling its teaching obligations, the laboratory undertakes research and development projects in collaboration with industry.
Prof. Dr.-Ing. Walter Czarnetzki Hochschule Esslingen Fakultät Maschinen und Systeme Labor für Wärme- und Strömungstechnik Kanalstraße 33 73728 Esslingen am Neckar
Striation optics to visualise density differences (speed, temperature, various gaseous media)
Soundproof cabin
Measuring devices
Measuring devices
Various measurement systems and methods are available, some of which are listed here:
Pressure (-1 to 2,500 bar)
Temperature with thermocouples, radiation pyrometer, thermal imaging camera
Speed measurement, air (0.1 to 40 m/s)
Volume flow, water (7.5 to 1,150 l/min)
Mass flow, air (3 to 1,000 kg/h)
Humidity (0 to 100% relative humidity)
Particle size measurement (1 to 400 µm)
Surface tension of liquids
Vibration measurement with acceleration transducers (1 and 3-dimensional, to 500g)
Sound intensity measurement, acoustic power
Measurement data recording and processing with LabView from National Instruments
Dynamic signal analyser for fast processes
Modelling techniques, visualisation
Small shallow water channel (measuring bench 500 x 700 mm)
Large shallow water channel (measuring bench 1,600 x 2,000 mm)
Small wind tunnel (cross-section 330 x 330 mm (450 x 450), 30 m/s)
Large wind tunnel (measuring cross-section Ø 700 mm, 60 m/s)
Smoke generator
Schlieren optics, interferometer (Object size to 25 cm) to visualise density differences
Thermal imaging camera
Flow simulation CFD
Simulation
Visualisation
To consolidate the lectures in thermodynamics, hydrokinetic flow machines and metrology, the following practical laboratory exercises are offered:
Thermodynamics laboratory
Refrigerating machine
Measurement of an anti-clockwise Clausius-Rankine cycle
Evaluation and graphical representation of the process
Humid air
State change humid air
h-x diagram
Psychrometer (measurement of relative humidity)
Stirling engine
Recording of the critical points
Evaluation and graphical representation of the process
Steam power process
Hydrokinetic flow machines laboratory
Shallow water channel
Transferability of fluid technology analogies with the aid of the laws of similitude and characteristic numbers in fluid engineering
Flow visualisation using models
Fan test bench
Calculation of the machine data from the measured values
Determination of the fan characteristic at different (rotational) speeds
Determination of the efficiency and graphic representation
Gas turbine
Measurement of various parameters and operating variables on a gas turbine for aircraft models
Evaluation of the measurement data and calculation of the characteristics of the cycle
Supersonic wind tunnel
Demonstration of a supersonic flow
Visualisation of a [super]sonic boom (Mach cone) with an interferometer
Metrology laboratory
Temperature experiment
Familiarisation with temperature sensors operating with different measurement principles and designs, as well as operation of measurement data recorders and software
Manual evaluation of the measurement data recorded to enhance understanding
Pressure measurement
Connection, setting up and operation of a measurement chain comprising a measurement amplifier and pressure sensor
Calibration of a pressure sensor.
Operation of and practice with a storage oscilloscope
Investigation of the dynamic behaviour of a pressure sensor in the event of a pressure jump
Flow rate measurement
Determination of the measurands at a Venturi nozzle and calculation of volume and mass flow
Calibration of a hot-wire mass air-flow sensor on a fan test bench
Evaluation.
Flow resistance and evaluation of measurement data
Determination of the flow resistance of compressed air hoses of different diameters.
Best-fit approximation of the measurement curve.
Measurement System Analysis
Exemplary investigation of the measurement system analysis using a caliper.
Electronic scale
Arduino programming and calibration of a bending beam.
Measurement of body geometry and NACA openings
The equipment and experience of the LWS have led to numerous contacts in various branches of industry. The activities are naturally in the field of metrology, thermodynamics and fluid dynamics engineering, but are not restricted to classical mechanical engineering.
Projects with a medical engineering background have also been undertaken in the past.
Depending on their size, the scientific investigations are conducted by one or more project groups and supervised by the specialist professors and laboratory staff.
Some project examples are listed below:
ApisJet
In this major project at the Institute of Applied Research, a glider of the type Apis 2 will be equipped with a jet engine. Instead of the existing retractable auxiliary engine with propeller, a jet engine will be used and act as the sustainer engine - the ultralight glider is not able to self-launch. Experiments and measurements for the individual projects are conducted in the LWS.
Voice prostheses
For patients who have had a full or partial laryngectomy, voice prostheses (small valve flaps) are inserted between oesophagus and windpipe to enable the patient to speak after such an operation. Measurement data is required to qualify these diaphragm valves. Student projects have involved developing an experimental set-up to measure the pressure-volume flow characteristic, the opening pressure and the long-term stability of different voice prostheses and performing related measurements.
Vibration studies on hand-held electrical equipment
Against the background of the European Directive 2002/44/EC (Physical Agents Directive Vibration), the relevant vibration measuring norms in the DIN EN 60745-1 and EN 60745-2-x standards for hand-held electric tools are currently being revised. The task of the R&D project was to carry out vibration measurements on hand-held electric tools to determine influencing factors such as the position and number of measurement transducers, practice measurements, wear of electric tools, etc. The objective of these investigations is not the direct comparison of machines from different manufacturers, but to improve the measurement method and obtain more detailed knowledge of the metrological interconnections.
Fuel cell battery
Part of the project was to set up a prototype and develop it further; this involved selecting components which are commercially available to set up a fuel cell system and using it for demonstration purposes in the laboratory.
