Analysis and Synthesis of Conical Coil Springs

Springs are mechanical devices that are employed to resist forces, store energy, absorb shocks, mitigate vibrations, or maintain parts contacting each other. Spring wires are commonly coiled in the forms of helixes for either extension or compression. Helical springs usually have cylindrical shapes that have constant coil diameter, constant pitch and constant spring rate. Unlike conventional cylindrical coil springs, the coil diameter of conically coiled springs is variable. They have conical or tapered shapes that have a large coil diameter at the base and a small coil diameter at the top. The variable coil diameter enables conical coil springs generate desired load deflection relationships, have high lateral stability and low buckling liability. In addition, conical compression springs can have significantly larger compression or shorter compressed height than conventional helical compression springs. The compressed height of a conical compression spring can reach its limit that is the diameter of the spring wire if it is properly synthesized. The height of an undeformed conical coil spring can have its height of its spring wire if the spring pitch is chosen to be zero. The variable coil diameter of conical coil springs provides them with unique feature, but also raises their synthesis difficulties. Synthesizing conical coil springs that require large spring compression or small deformed spring height or constant spring rate is challenging. This research is motivated by surmounting the current challenges facing conical coil springs. In this research, independent parameters are introduced to control the diameter and pitch of a conical coil spring. Different conical coil springs are modeled. Their performances are simulated using the created models. The deflection-force relationships of conical coil springs are analyzed. The results from this research provide useful guidelines for developing conical coil springs.

Investigation of a novel solar powered trigeneration system for simultaneous production of electricity, heating, and refrigeration below freezing

A solar powered trigeneration system consisting of tower solar collector, Kalina cycle with the heat exchanger, and EARC is proposed to produce refrigeration below freezing, electricity, and process heat, simultaneously. Simulation through CFD using ANSYS-FLUENT package is conducted to examine the effect of coil diameter and inlet oil temperature on the pressure and temperature of SHTF. It is found that, for inlet temperature of 92oC and DNI 850 W/m2, the SHTF outlet temperature increases by 9% when the coil diameter increased from 150 to 400 mm. Trigeneration performance is analyzed after altering; hot oil outlet temperature, turbine entry pressure, and the concentration of ammonia-water basic solution to study their effect on power produced by turbine, refrigeration load, exergy of refrigeration, and efficiencies of trigeneration system. Increase in concentration of ammonia-water basic solution is leading towards the significant increase in the turbine power and the elevation of trigeneration system’s energy and exergy efficiencies. Bottoming of Kalina cycle with EARC shows the distribution of solar energy as; energetic output 72.31% and energy lost to environment 27.69%. The solar exergy supplied to the trigeneration system is distributed as; 16.23% exergy is produced, 1.62% is the exergy loss, and 82.15% is the exergy destroyed.

A Simulation Magnetic Induction Tomography (MIT) for Agarwood using COMSOL Multiphysics

Magnetic induction tomography is an imaging technique used to image electromagnetic properties of an object by using the eddy current effect. (MIT) is a non-destructive method that greatly is used in the agriculture industry. This method provided an opportunity to improve the quality of agricultural products. MIT simulation was used for agarwood existence detection. This paper presented for the simulation system contains 7 channel coils receiver and a channel transmitter which is a sensing detector. This experiment aims to demonstrate the reaction of induced current density and magnetic field at 10 MHz frequency. Then, it also determines the optimal solenoid coil to be used for a better outcome for the magnetic induction system. The simulation result shows that coil diameter, coil length, and coil layer have a crucial role in the great performance of the induced current and magnetic field. The more coil turns, the greater the strength of the permanent magnetic field around the solenoid coil. The result of the simulation is important and needs to be considered to verify the effectiveness of the system for developing the magnetic induction circuit design.

Application of inductive coupling for wireless power transfer

Considering the massive development that took place in the past two decades, wireless power transfer has yet to show the applicability to be used due to several factors. This work focuses on determining the main parameters like, mutual inductance, and coupling coefficient for a pair of helical coils for wireless power transfer applications. These parameters are important in designing and analyzing a wireless power transfer system based on the phenomenon of inductive/ resonant inductive coupling. Here presents a simple approach based on fundamental laws of physics for determining the coupled coil parameters for single layered helical coils. The results conducted by computer simulation which is MATLAB. Furthermore, this analysis is used to study the effect of change in coil diameter, mutual inductance coefficient and change in distance between coils on parameters like self and mutual inductance of coupled coils which is of great importance in Wireless Power Transfer applications. The research yielded promising results to show that wireless power transfer has huge possibility to solve many existing industrial problems.

Comparative Study on a Straight and Helical Capillary Tube for CO2 and R22 Refrigerant

A comparative study has been carried out on the adiabatic straight and helical capillary tube, using a CO2 and R22 refrigerant. The numerical model for CO2 and R22 is developed using the basic principles of conservation of mass, momentum, and energy. The effect of coiling in the helical capillary tube is compared with a straight capillary tube for CO2 and R22 refrigerant. Compared with the straight capillary tube, the percentage reduction in mass flowrate in the helical capillary tube is calculated with a change in coil diameter, tube diameter, and length. As the coil diameter increases from 30 mm to 150 mm, the percentage reduction in mass is from 5.8% to 2.2% in CO2, and 5% to 1.6% in R22. For helical capillary tube with 50 mm coil diameter, as the tube diameter increases from 1 to 1.5 mm, the percentage reduction in mass flowrate with CO2 refrigerant is from 2.65% to 4.96%, however, for R22 it is from 2.43% to 4.24%. Similarly, as the capillary tube length increases from 1.3 m to 1.8 m, the percentage reduction in mass with CO2, with 50 mm coil diameter is 4.44–4.55%. However, the percentage reduction in mass with R22 is 3.71–3.85%. Moreover, compared with the straight capillary tube, the percentage reduction in length in a helical capillary tube with coil diameter 50 mm is 16% for CO2 and 9% for R22 refrigerant.

CFD Study of Pitch Variations On Helically Coiled Pipe in Laminar Flow Region

Experimental investigations of the flows inside helically coiled pipe are difficult and may also be expensive, particularly for small diameters. Computational fluid dynamics (CFD) packages, which can easily construct the geometry and change the dimensions with 100% of accuracy, provide an alternative solution for the experimental difficulties and uncertainties. Therefore, a computational fluid dynamics (CFD) study was conducted to analyse the flow structure and the effect of varying the coil pitch on the coil friction factor, through utilising different models' configurations. Two coils were tested, all of them sharing the same pipe and coil diameter: 0.005m and 0.04m respectively. Pitch variations began with 0.01 and 0.05 m for the first, second model respectively. In this study, the velocity was analysed, and the effects of this reduction on coil friction factor were also examined using laminar flow. The results were validated by Ito's equation for the laminar flow.

Performance of air source air conditioning water heater using trombone coil dummy condenser with different diameter and pipe length

The Air Source Air Conditioning Water Heater (ASACWH) performance as an energy source to heat water in the tank using dummy condenser type of trombone coil with different diameter and pipe length without hot water circulation has been investigated. The diameter and length of the dummy condenser pipe are intensely affected by ACWH performance. In this study, cooling capacity, Coefficient of Performance (COP), compressor power and room temperature were evaluated in three types of trombone coil (6.4 mm coil diameter with a length of 7.9 m, 6.4 mm coil diameter with a length of 5.3 m, and 9.5 mm coil diameter with a length of 5.3 m) with different cooling load variation. This study used cooling load with a variation of 0 W, 1000 W, 2000 W, and 3000 W without hot water circulation in the simulation room. It was found that the ASACWH using a pipe with a coil diameter of 6.4 mm and length of 7.9 m performed the highest cooling capacity and COP, and produced more comfortable room temperature than the other two pipes. The results indicated that when the cooling load icreased from 0 W to 3000 W, the compressor power increased by 11.3%, 6.3%, and 9.3%, using the 6.4 mm coil diameter with 7.9 m length, 6.4mm diameter of the coil with 5.3m length and 9.5mm coil diameter with 5.3m length, respectively.

Analysis of the Influence and Number of Turns on the Smartphone Wireless Charger on the Output Power of the Wireless Charger

Charging the smartphone battery can be done via powerbank or default charger from the smartphone still using the cable for charging the electricity. Charging using a cable certainly limits the use of the smartphone when it is charging. Smartphone users can not be far from the electric socket which of course is troublesome if this happens in the middle of a room that has a few electrical sockets. To solve this problem, now many wireless charging smartphones or smartphones have been developed wireless charger. Behind the benefits obtained from a wireless charger, it also has disadvantages, namely the transmission distance is short, even there is no distance and the transmitted power is unstable. Wireless chargers are based on the principle of magnetic induction in which electricity is transferred between two objects through a coil. Wireless charger consists of the primary coil as a charger (usually in the form of a thin board or cylinder), and the secondary coil is located on the back of the cellphone. Based on the results, the output power is obtained. The largest wireless charger is 0.027W with a coil diameter of 8cm in all the number of primary coils, namely 40 turns, 50 turns, and 60 turns at a primary and secondary coil distance of 0cm to 1cm. The farthest distance from the wireless charger output power test is 6cm as well as the 8cm coil diameter for all the number of primary coil turns, namely 40 turns, 50 turns, and 60 turns.

Wireless Power Hanger Pad for Portable Wireless Audio Device Power Charger Application

Since the portability feature has been introduced in headphone development, this device now uses a battery as the main built-in power. However, the battery has limited power capacity and a short lifetime. Battery substitution and a conventional battery charger method is an ineffective, inflexible inconvenience for enhancing the user experience. This paper presents an innovative portable audio device battery built-in charger method based on wireless power technology. The developed charging device is composed of a headphone hanger pad for the wireless headphone and a charging pad for the portable wireless audio device battery charging. Circular flat spiral air-core coil was designed and evaluated using a numerical method to obtain optimal vertical magnetic field distribution based on the proposed evaluation criteria. A coil has inner coil diameter of 25 mm, outer coil diameter of 47.8 mm, wire diameter of 0.643 mm, the pitch of 0.03 mm and a number of turns of 17 was chosen to be implemented on the transmitter coil. A magnetic induction technique was adopted in the proposed wireless power transmission module which was implemented using commercial off-the-shelf components. For experimental and validation purposes, a developed receiver module applied to the commercial wireless headphone and portable audio speaker have a built-in battery capacity at 3.7 V 300 mAh. The experimental results show that the wireless power hanger pad prototype can transfer a 5 V induction voltage at a maximum current of 1000 mA, and the power transfer efficiency is around 70%. It works at 110 kHz of operation frequency with a maximum transmission distance of about 10 mm and takes 1 h to charge fully one 3.7 V 300 mAh polymer lithium battery.