FLUID MECHANICSTO MAZHAR IMAM LAB MANUAL AGHA DANISH ILYAS Roll no D-12-CH-113 3rd semester ____________________ Teacher ____________________ Date AGHA DANISH ILYAS ROLL NO.FLUID MECHANICS 2 This certificate is awarded to AGHA DANISH ILYAS Enrolled in D. 113 .C.T as a regular student of BE – Chemical In the following batch and bearing roll number 2012 – 113 This is to certify that he has completed the required task and fulfilled all the requirements of the given task and submitted the lab manual according to the given schedule.E. FLUID MECHANICS S no. Date experiments To Study Methods of unit WL202 3 Page no. remarks signature 1 4-5 6-7 Temperature Measurement by a 2 To study the process unit control pressure UCP-P 8-9 3 To study the process occuring in a fluidization and fluid bed heat transfer unit H693 To study the process of sedimentation ESED 4 10-11 AGHA DANISH ILYAS ROLL NO. 113 . FLUID MECHANICS 4 EXPERIMENT NO # 1 Methods of Temperature Measurement by a unit WL202 Introduction Many physical phenomena (e. a plotter. As well as non-electrical measuring methods.g. etc. thermocouple type K. such as gasand liquid-filled thermometers and bimetallic thermometers. A digital multimeter with precision resistors is used to calibrate the electrical measuring devices. enabling temperature characteristics to be recorded with. 7 mercury thermometer. Temperature measurement devices can be classified as mechanically operative or electrically operative Apparatus The WL 202 experimentation set-up covers the full range of temperature measurement methods. electrical resistance. thermistor (NTC). 10 digital display. Temperature variations affect these quantities. 8 digital display. expansion coefficients. 9 digital display.10V) is accessible from lab jacks. 5 bimetal thermometer. Various heat sources or storage units (immersion heater. A plastic casing houses the sensors.) can be related to temperature through the fundamental molecular structure. Theory Liquid thermometer: practically all liquids can be used in thermometers but other liquids (except mercury) cause additional errors as the temperature drops. and hence their changes can be used to indirectly measure temperature. PT100. pressure. The electronically measured temperatures are displayed directly on programmable digital displays. 1 power-regulated socket. And must be colored so that it is visible in the capillary tube and the reading of AGHA DANISH ILYAS ROLL NO. 2 laboratory heater for water and sand. 11 multimeter. 113 . cables. volume. 4 gas pressure thermometer. 6 vacuum flask. all typical electronic measuring methods are covered in the experiments.. temperature measuring strips and immersion heater. 3 psychrometer to determine air humidity. A temperature-proportionate output voltage signal (0 . for example. vacuum flask and laboratory heater) permit relevant temperature ranges to be achieved for the sensors being tested. which generate approximately 40 microvolts per °C of couple temperature difference. Each junction forms a thermocouple.FLUID MECHANICS 5 the temperature made easier. and pressure is the thermometric property. In its basic form it consists of two dissimilar metallic conductors connected in a closed loop. Atmospheric humidity can be determined using a psychrometer. If one thermocouple is maintained at a temperature different from that of the other. and a highly nonlinear characteristic A semiconductor which exhibits rapid and extremely large changes in resistance for relatively small changes in temperature. The value varies with the materials used. For this purpose two thermometers are fitted to a board. and volume is the thermometric property. Thermistor: Semiconductor resistance temperature sensors (thermistors) are more sensitive than RTDs. The gas thermometer is the most accurate of all thermometers and is used as the standard instrument for measurement of temperature. Psychrometer: An instrument used to measure the water vapor content of the air. Such thermometers can be made with very short time constants and are capable of highly accurate measurements. the sensitive element of which consists of two metal strips which have different coefficients of expansion and are brazed together. are often used for meteorological purposes. -Bimetallic thermometer: A thermometer. They have a very large negative coefficient. The distortions of the system in response to temperature variations are used as a measure of temperature. Liquid containers for mercury are larger than for other liquids due to the smaller coefficient of expansion. and (b) a type in which the gas is kept at constant pressure. an electrical current proportional to this temperature difference will flow in the circuit. 113 . Couples of copper and constantan. -Gas thermometers: A thermometer which utilizes the thermal properties of gas. There are two forms of this instrument: (a) a type in which the gas is kept at constant volume. One thermometer measures the temperature at atmospheric humidity. Resister thermometers (RTD): A type of electrical thermometer in which the thermal element is a substance whose electrical resistance varies with the temperature. A type of hygrometer. AGHA DANISH ILYAS ROLL NO. The second thermometer measures the temperature at 100% humidity. It consists of a wet-bulb and a dry-bulb thermometer. Thermocouple: A temperature-sensing element which converts thermal energy directly into electrical energy. resistances.FLUID MECHANICS EXPERIMENT NO # 2 To study the process unit control pressure UCP-P 6 Anodized aluminium structure. Proportional control. of all the process/system responses. without necessity of changes or connections during the whole process test procedure. control valves. Intel/outlet valve. All the actuators’ values can be changed at any time from the keyboard allowing the analysis about curves and responses of the whole process. Storage tank. Diaphragm. to +10V. etc. by changing the values. Real time curves representation about system responses. at any moment during the process. computer output. Sensors connectors in the interface have different pines numbers (from 2 to 16). Three safety levels. 113 . integral and derivative constants). The unit control elements are permanently computer controlled. Control interface box with process diagram in the front panel and with the same distribution that the different elements located in the unit.Exhaust valve. with their respective signals. Panels and main metallic elements in stainless steel. Flow meter. of parameters involved in the process simultaneously. are properly manipulated for -10V. Possibility of automatization of the actuators involved in the process. Single cable between the control interface box and computer. AGHA DANISH ILYAS ROLL NO. in real time. integral control and derivative control. Simultaneously visualization in the computer of all parameters involved in the process. Pressure manometers. at any time. All the actuators and sensors values and their responses are placed in only one computer screen. Pneumatically Operated Control Valve.and a diagram in the front panel with similar distribution that the elements in the real unit. other electronic in control interface and the third one in the control software. Differential Pressure Sensor. Real time PID and on/off control for pumps. at any time and in a real time . Open control allowing modifications. Real time PID control for parameters involved in the process simultaneously. Graphic representation. compressors. to avoid connection errors. Storage of all the process data and results in a file. Pressure Sensor. one for controlling the pneumatic operated control valve and the second supplies the necessary flow and/or pressure to the circuit that is to be adjusted. Real time PID control with flexibility of modifications from the computer keyboard of the PID parameters. for an easy understanding by the student. Shield and filtered signals to avoid external interferences.All sensors. one mechanical in the unit. I/P Converter. Calibration of all sensors involved in the process. On/off valves.Pressure regulators. based on the real PID mathematical formula. of the three control constants (proportional. the working of a pneumatic control valve is automatic adjust the flow of a fluid by the reference pressure. there are two paths for the fluid 1) if a fluid has some dust particles or some other impurity so we pass it through a tank in which a fluid is stored and refined by the filtration process this path is called indirect path 2) if our fluid is free from undesired particles so fluid is pass through a direct path After that some sensors are installed in a unit to observe the pressure one of the sensor is Differential pressure sensor At last there are two paths for the outgoing of fluid 1) If it is required to measure the volumetric flow rate gas is pass through a rotameter which measure pressure and also use to control a flow rate from a outlet 2) The second path is to directly take out the fluid from a unit AGHA DANISH ILYAS ROLL NO. 113 . After fluid passing through a compressor it enter in a unit where valves are present to control flow after that fluid passes through the Pneumatic control valve.FLUID MECHANICS 7 Process occurring in a unit: Process unit control pressure is use to control a pressure and flow of a fluid especially gas. In this unit to generate a pressure compressor is used. Heat Transfer in Fluidized Beds Heat transfer in the fluidized bed is. the most important process contributing to the intensity of the physical and chemical processes. 6-25 W/m2°C. when leaving the bed. Bed types can be coarsely classified by their flow behavior. is practically the same as the particle temperature. The large heat capacity of the solid AGHA DANISH ILYAS ROLL NO. All of these heat transfer processes are very intensive in fluidized beds. This is usually achieved by the introduction of pressurized fluid through the particulate medium. with some fine particles being entrained. Intensive heat transfer is. even 1000°C.FLUID MECHANICS EXPERIMENT NO # 3 8 To study the process occuring in a fluidization and fluid bed heat transfer unit H693 FLUIDIZATION A mass of solid particles that is made to flow like a liquid by injection of water or gas is said to have been fluidized. 113 . In water treatment. heat transfer between different points in the bed. with mean bed temperatures of several hundred. although heat transfer coefficients to the particles in the bed are relatively small. the temperature difference between points in the bed does not exceed 2-5°C. In the case of uniform fluidization. a bed of filter media is fluidized by backwashing water through the filter. Circulating fluidized beds (CFB). FLUIDIZED BED A fluidized bed is formed when a quantity of a solid particulate substance (usually present in a holding vessel) is placed under appropriate conditions to cause the solid/fluid mixture to behave as a fluid. a consequence of the large specific heat transfer surface (3000 to 45000 m2/m3). or to be pumped using fluid type technologies. Gas temperature. This results in the medium then having many properties and characteristics of normal fluids. apart from the particle and gas mixing. such as the ability to free-flow under gravity. Annular fluidized bed (AFB). heat transfer between the fluidized bed particles and the larger particles floating in the bed and the heat transfer to the submerged surfaces in contact with the bed. In fact. several different processes can be distinguished: particle-gas heat transfer. first of all. These facts tell us of the great capability of the solid particles to exchange heat with the fluidizing gas. including : Stationary or bubbling bed is the classical approach where the gas at low velocities is used and fluidization of the solids is relatively stationary. Application Use of liquid/solid fluidization techniques for size classification is a common practice in mineral processing operations.5 mm) is not straightforward as these fine size particles tend to remain in a mixed state during fluidization. and may use cryogenic or vapor-compression refrigeration. Taking an example from the food processing industry: fluidized beds are used to accelerate freezing in some IQF tunnel freezers (IQF means Individually Quick Frozen. AGHA DANISH ILYAS ROLL NO. shrimp or sliced vegetables.FLUID MECHANICS 9 particles also makes the temperature difference between gas and particles small. Extending its application in gravity separation for finer feed particles (− 0. Gas temperature follows the particle temperature. or freezing unpackaged separate pieces). Separation is effective within a limited range of size (ratio) with proper control on superficial water velocity. These fluidized bed tunnels are typically used on small food products like peas. that's why it is also used to catalyze the chemical reaction and also to improve the rate of reaction. 113 . The fluid used in fluidized beds may also contain a fluid of catalytic type. In a longitudinal flow. the applied force accelerates the particles to a terminal velocity at which the applied force is exactly canceled by an opposing drag force. the drag force varies linearly with the terminal velocity. This includes particles of a size not lower than 10 μm. Colloids are particles of a size between 0. Solid particles entrained by the turbulence of moving water may be removed naturally by sedimentation in the still water of lakes and oceans. the ascending water velocity is lower than the limit sedimentation velocity. the ratio of the length of the tank to the height of the tank is higher than the ratio of the water velocity to the limit sedimentation velocity. .. PROCESS OF SEDIMENTATION Sedimentation is a physical water treatment process using gravity to remove suspended solids from water. it is generally possible to define a sedimentation AGHA DANISH ILYAS ROLL NO.001 µm and 1 µm depending on the method of quantification. Similarly. is the mass of dry solids retained by a filter of a given porosity related to the volume of the water sample. For small enough particles (low Reynolds number). (Stokes flow) where f depends only on the properties of the particle and the surrounding fluid. i. and come to rest against a barrier. 113 . In settling process theory. 2. the applied force generally varies linearly with some coupling constant (denoted here as q) that depends only on the properties of the particle. a particle will settle only if: 1. Sedimentation is the deposition by settling of a suspended material.FLUID MECHANICS EXPERIMENT NO # 4 To study the process of sedimentation ESED SEDIMENTATION 10 Sedimentation is the tendency for particles in suspension to settle out of the fluid in which they are entrained. they are not likely to settle naturally. Hence. Settling basins are ponds constructed for the purpose of removing entrained solids by sedimentation. Experiments In a sedimentation experiment called tripothsis. Because of Brownian motionand electrostatic forces balancing the gravity. SEDIMENT Any particulate matter that can be transported by fluid flow and which eventually is deposited as a layer of solid particles on the bed or bottom of a body of water or other liquid. In a vertical ascending flow. Suspended solids (or SS).e. The limit sedimentation velocity of a particle is its theoretical descending speed in clear and still water. Thus. The sedimentation coefficient s in this case equals . the motion of the particles is blocked by a hard boundary. whereas in the Mason–Weaver equation gravity is constant. which likewise has an exact solution. The Lamm equation also has extra terms. 113 . whereas the Mason–Weaver equation is one dimension AGHA DANISH ILYAS ROLL NO. since it pertains to sector-shaped cells. However. The sedimentation of a single particle under gravity is described by the Mason– Weaver equation. where is the buoyant mass. where is the buoyant mass. measuring s can reveal underlying properties of the particle. In many cases. which has a simple exact solution. The sedimentation of a single particle under centrifugal force is described by the Lamm equation. the Lamm equation differs from the Mason–Weaver equation because the centrifugal force depends on radius from the origin of rotation. The sedimentation coefficient s also equals .FLUID MECHANICS 11 coefficient that depends only on the properties of the particle and the surrounding fluid. The concentration of particles at the boundary is opposed by the diffusion of the particles. the resulting accumulation of particles at the boundary is called a sediment.