Measurements analysis and designs see attached file
Paper Experimental Design Proposals Spring 202 1 Due on the last day of c lasses – May 11 Your proposed experimental designs should include the following • Restatement of the pro ble m as you see it. • Ex planation of hand or Matlab calculations us ed to s upport your design. • Uncertainty calculat ions when possible • Scans or images of equipment specifications . Choose sp ecific models when appropriate and include web links . Specify amplifier types when necessary . • Drawings of exper imental s etup . Neat hand drawings are fine. Don ’t bother with SolidWorks unless you are very pro ficient. Powe rPoint s chematics are suggested. • References (can be web sources). I am not requ iring a specific format. Just remember that the more cohesive and organized it is, the easier it is to grade and grade a ccurately. You should do your own work . You may ask questions of me or Ivo. We are using the TA ’s for other aspects and want to make sure the answers are cons istent. We will post any new information on the assignment page if we determine that you need more information. 1. Design a Couette viscometer to measure fluids with viscosity as low as 0.1 c P (centipoise) and as high as 10 cP with an uncertainty of 1%. Propose two designs, one where you measure torque using a force sensor and one where you infer the torque from the motor. • You need to specify the dimensions of the inner and outer cylinders. • You need to justify the proposed uncertainty of your measure ment . • You need to specify how you calibrate the system. • You need to specify how you will process the output to get viscosity. • The first case will require you to specify a force sensor type and range. You need to either design one or propose a commercial, off -the -shelf sensor . Use as much of the component specifications in your estimate of uncertainty (e.g. linearity, resolution, etc.) • You can assume that a motor will follow a linear, torque -RPM relationship and will need to specify a motor type (stall tor que, motor constant) . Describe how you will calibrate the motor . 2. Design a load cell -based truck scale with 0.1% uncertainty. Assume the trucks will range from 10,000 lbs. to 80,000 lbs. and will be no more than 60 feet long. • The platform must be larg e enough to accommodate the truck and support its weight. Assume it is fabricated from 1 inch thick steel. You can consider counter bal ances if th e weight is too large. • You need to select a commercial load cell (s) . • You need to consider the impact of temperature variations from -10 oF to 120 oF. • The maximum displacement of the platform cannot exceed 1 inch. • Propose w hat the resolution will be if the 10 lb. resolution cannot be met. 3. Design a water tunnel to study super -cavitating cylindrical objects with a dimeter of at least 1 inch. The impeller and motor were selected and you can achieve a maximum volumetric flow rate of 280 l/s. The test section should have a square cross -sectional area (to allow optical measurements) and the piping upstream of the contraction was already designed to have a diameter of 18 inches. • Select the size of the object and the size of the test section so that you can achieve maximum speeds of at least 10 m/s while having blockage ratio of no more than 10%. • Propose a system that uses pressure sensor(s) to measure the speed in the test section. The pressure sensors should not protrude i nto the tunnel to avoid flow disruption, but you can measure the static pressure (perpendicular to the flow surface) at any point of the tunnel.Specify what pressure sensor(s) you should use and where do you plan on installing them. What range of velociti es will you be able to measure and with what accuracy? • You able be able to independently control the pressure in the test section down to 20 kPa and up to 200 kPa at any speed, by applying pressure/pulling vacuum at the top surface of the water (which is about 1 meter above the test section). Specify what pressure sensors you will use to evaluate the static pressure in the test section and identify how accurately you can measure it. • What is the minimum cavitation number you can achieve and what is its uncertainty if you are not able to drop the pressure in the test section below 20 kPa (because of air leaking in)? The cavitation number σ = (p – pv)/(0.5ρU 2) where p is the pressure in the test section, p v is the vapor pressure of water (the pressu re at which water will turn to vapor at the temperature at which it currently is), ρ is the density of water and U is the test section water velocity. Assume you fill the tunnel with filtered water (it has a minimal amount of dissolved solids). What other sensor do you need to measure the cavitation number for the tests? At what Re number will you be able to achieve the lowest cavitation number and what is the uncertainty of the Re number? • Propose at what velocities and pressures you should test the cylind rical body so that you can achieve the same cavitation number for three different Reynolds numbers Re = x; Re = 1.5*x, and Re= 2*x. Without modifying the water tunnel itself, what can you do achieve a wider range of Re numbers while maintaining the same ca vitation number?
