# Physics projects for Y3 and Y4 students

## Project description

### Efficient Drying of Clothes on Washing Lines

#### (supervisor: Tony Cook)

Nature of project: experimental, data analysis

Available to students on full-time physics degree schemes or joint students.

#### Project description and methodology

Drying clothes outside has not changed much for several centuries. You hang the clothes up, and use a combination of gravity fed dripping, evaporation from solar heating, and evaporation from forced convection. The cost of using a tumble drier, or placing clothes of radiators, pushes up your electricity and heating bills. Drying clothes outside though is not much fun, especially with mixtures of sunshine and showers becoming seemingly more common place. If we could devise a more efficient and faster way to dry clothes outside, think of the commercial possibilities? Are there any optimal design for rotary clothes lines that could lead to faster drying. You will experiment in the laboratory with forced convection, heat sources (e.g. a bright tungsten lamp to simulate the Sun), and standard sheets of fabric.

A successful project will develop beyond the above in one/some of the following directions:
1) Investigate different tilt angle of clothes (if held on a wire mesh support) wrt to the heat source, local vertical, and wind direction.

2) Investigate gaps between clothes, arrangement of clothes such that the more soggy ones are at the back (or front)?

3) Could a propeller or sail be added to make a clothes line rotate faster to add extra centrifugal force.

4) Could some specially shaped obstruction be placed on the ground to capture heat and radiate it upwards (to increase air flow over the clothes) help improve drying efficiency?

When considering where to take your project, please bear in mind the time available. It is preferable to do fewer things well than to try many and not get conclusive results on any of them. However, sometimes it is useful to have a couple of strands of investigation in parallel to work on in case delays occur.

Additional scope or challenge if taken as a Year-4 project: Utilize a thermal imaging camera to monitor progress of evaporation across the textile material as a function of time.

Please speak to Tony Cook (atc) if you consider doing this project.

Initial literature for students:

1. Bone, W.A. and Turner, H.A. (1950) Some Effects of the Evaporation of Water from Cotton Cellulose. (1950) Journal of the Society of Dyers and Colourists, 66,315.
2. http://www.conservationphysics.org/wetstuff/wetstuff01.php
4. http://www.eytest.com/images/aatcc195-2011.pdf

#### Novelty, degree of difficulty and amount of assistance required

This is an average level difficulty project. Some construction skills might be useful.

In case of a COVID lockdown happening, I wouldadvise students to only attempt this project if they have access to a clothes line in a garden. You can probably borrowlab equipment such as scales to measure the weight of clothes as they dry.

#### Project milestones and deliverables (including timescale)

milestoneto be completed by
Decide which textiles to use, sizes, equipment etcend of November
Plan set up of equipment/construction of clothes lineChristmas
Test drying with different textures at different angles of illuminationend of February
Investigate effects of convection on drying ratesmid-March

Students taking this project will have to submit a full risk assessment form