n= polytropic exponent. The reference for the design equations is the book “Compressors – Selection and Sizing” by Royce N. Brown which I personally consider amongst the best books for compressors. So kinetic energy shouldbe expressed in kJ/kg. Compressor Finder & Calculator. Juan Reca-Cardeña, Rafael López-Luque, in Advances in Renewable Energies and Power Technologies, 2018. Because the stagnation enthalpy entering the free turbine ht,5 is fixed by the other parameters, as set out earlier, we may approximate the stagnation enthalpy drop in Equation (10.64) as follows: Because only the second and third terms are variable, we may take the derivative of Equation (10.69) with respect to Ve and set it to zero to find the value of the extreme point, which is, Because the second derivative of Equation (10.69) is negative, the value for Ve given by Equation (10.70) is a maximum. The air heats up as it … This value needs to be multiplied by the number of cylinders to find out the capacity of the reciprocating compressor. Room Area: 79 m2 since using the polytropic efficience [(k-1)/k]/[(n-1)/n] will be greater than 1. Finest individual proxies just from DreamProxies.com. Diesel engines require only minor modification to burn these fuels (but employ small amounts of diesel fuel to provide ignition). The rotary type (either axial or centrifugal flow) 2. We will compare the rigorous method results with the values from the short cut methods. i am by no means a mathematician and all these equations are really confusing me. We used only the ProMax calculated values of polytropic efficiency (nP), compression ratio (P2/P1), and relative density (y). Actually power required to drive the compressor is greater than the indicated power. Raise compression ratio to power of (k-1)/k or CR=(P2/P1)^[(k-1)/k] Dear Dr. Mahmood, Second, from the head, the actual work, discharge pressure and finally the discharge temperature are calculated. Dr. Moshfeghian joined JMC This is because a gas engine actually produces power through its own combustion, while electric motors draw their power from an external system. Mechanical losses are not a function or percentage of gas horsepower and must be calculated. At lower temperatures (typically lower than −40°C), complex refrigeration schemes, such as cascaded refrigeration cycles, may be needed, increasing the complexity of the models used to predict the power requirements. This holds also true for oil and gas production sites that need to be able to operate in an island mode disconnected from electric grids. Is it possible for me to send the procedure for you to check if that is correct or not? Compare carefully. Running hours. 2. k=Cp/Cv is the ideal gas heat capacity ratio. I hope this helps. The block uses two-way ports to connect to the inlet and outlet control volumes and the drive shaft. This leaves Equation (10.65) with two unknowns: free turbine pressure drop and jet exit velocity. To get the shaft speed, w ---w = (2*pi/60)*(rpm) [rad/s] and shaft power is SP = w * T [=] (rad/s)*(ft-lb) = ft-lb/s or [=] (rad/s)*(m-N) = m-N/s = J/s = W To get shaft horse power, it is only necessary to convert ft-lb/s to hp. Determination of the influence of intercooling on the required shaft power (from p2/p1G, K, = T, T1 and estimated number of intercoolings per casing j) with Diagram 6 f= 0.91 with ΔT =0 and j = 1 11. This kinematic model is further extended to present a … P in Watt = Here. He has 40 years At too high a pressure ratio the low combustor temperature rise offsets the low exhaust temperature, which reduces thermal efficiency. The discussion will be limited to engines operating on biomass or a fuel derived from biomass, since biomass is the main indigenous fuel source in most developing countries. This article provides relationships to determine the required pump power. 10. ηM is the efficiency of the asynchronous motor, and this efficiency increases as the frequency of the electrical current diminishes. 2. Compressor Coupling Size 1-1/4” from information given by maker. The rate is usually obtained by timing how long it takes a compressor to fill a BA cylinder, perhaps an 80 cf SCUBA cylinder, from 0 to 3000 psig. V d =Swept volume (m3) V s =Actual volume capacity (m3) V c =Clearance volume (m3) c=clearance=V c /V d =Swept volume (m3) E v =volumetric efficiency (-) τ=compression ration = p discharge / p suction (-) St=Piston Stroke (m) to make sure they don’t miss a thing. The Compressor block simulates engine boost by using the drive shaft energy to increase the intake manifold pressure. ProMax 3.2, Bryan Research and Engineering, Inc, Bryan, Texas, 2011. Available Power is based on the selected engine output power and is for a new engine at nominal performance, optimum speed and ISO conditions. Any one of these processes can be used suitably as a basis for evaluating compression power requirements by either hand or computer calculation. The shaft power - the power required transferred from the motor to the shaft of the pump - depends on the efficiency of the pump and can be calculated as. The unit of ke is m2/s2which is equivalentto Joule/kg. When indicated in the data sheet theoretical capacity of compressor unit shall be recalculated for capacity at outlet, thus, to decrease the value by 30-40%. We now turn to the denominator. Measure suction pressure (P1), suction temperature (T1), and discharge pressure (P2), discharge temperature (T2). The turbine may also have to provide work for some accessories, such as pumps or generators, but for clarity and compactness that incremental work is neglected here because it is small in magnitude. Pump Power Calculation. Simple Energy Formula: Motor Efficiency = Cost per KW X .746 (Power Factor) ... Download Air Compressor Calculations. k = 1.41 = adiabatic expansion coefficient. Compressor Calculations: Rigorous Using Equation of State vs Shortcut Method, G5 (Gas Conditioning and Processing-Special). He holds B.S. Before you paint ceiling and walls, follow the 9 feet Gas turbine for mechanical drive applications (7 MW). The calculated discharge temperature by equation 4A (isentropic path) was exactly the same as by equation 4B (polytropic). I had put up a query about how to use compressibility factor for calculating adiabatic discharge temperature? For known gas rate, pressure (P1), temperature (T1), and composition at the inlet condition and discharge pressure (P2­), computation of compressor power requirement is based on an EOS using a computer and involves two steps: The efficiency of the compressor, and hence, the compression process obviously depends on the method used to evaluate the work requirement. The block uses two-way ports to connect to the inlet and outlet control volumes and the drive shaft. T2 = 134 °C. Compressor polytropic efficiency. Order to learn how to share knowledge about your scribd member to calculate gas. The lower of the two results will indicate the transition point where an impeller specifically designed for laminar flow, such as an anchor or helical ribbon, must be used. The thrust power developed by the turboprop may be written as, The first assumption implicit in this equation is that the fuel to air ratio (f/a) is about equal to the fraction of air bled from the compressor for various purposes, such as turbine blade cooling, so that the mass flow of gas passing through the engine may be considered constant. k=Cp/Cv is based on the ideal gas heat capacity ratio. In any case it will not be discussed further here. The hydraulic power which is also known as absorbed power, represents the energy imparted on the fluid being pumped to increase its velocity and … The optimum pressure ratio for thermal efficiency increases with SOT, being 12:1 at 1100 K and rising to over 40:1 at 1800 K. The fact that there is an optimum is because as well as high combustion temperature rise, high thermal efficiency also requires low exhaust temperature to minimize energy wastage. Answer: Shaft Power = 47 kW. In the developing countries, where electric energy is often not available where power is needed, internal combustion engines using a petroleum fuel are frequently used in stationary applications. Note the short-2 results (discharge temperature, adiabatic and polytropic heads and power) are deviated from the SRK values. These calculated results are presented in the SRK columns of Table 2 (bold numbers with white background). ı have tow things Notice that the CPR is also related to the total temperature ratio across the compressor. Please Sir,how do i find d expression for entropy for a soave-redlich kwong equation of state ? The required power of the air compressor can be determined by calculation according to the theoretical process occurring in air compressor (when calculating with isothermal and adiabatic compression, appropriate correction shall be made to the actual cycle), or the indicator diagram drawn when testing the air compressor with the experimental square root saw. So decide if you are irritated, or happy with the color and Direct conversion of chemical energy in biomass to mechanical power by use of animals is discussed in Chapter 10. The compressor–burner–turbine unit would be essentially a hot gas generator for the free turbine. Calculation of the centrifugal gas compressor shaft power and efficiency related parameters performed. Contact Lewis Systems, Inc. for Air System Services. For example, if the motor efficiency is 95% then 105 HP must be applied to the motor to overcome the losses to produce 100 HP of shaft input. The results of a reversible process are then adapted to the real world through the use of an efficiency. More detailed analysis of the turboprop engine may be found in Mattingly (1996). Note that the accuracy of the shortcut method is dependent on the values of k and n. In Short-1 method in which we used the k and n values from the SRK method the results were identical to those of SRK method. Academic year. The required power of the air compressor can be determined by calculation according to the theoretical process occurring in air compressor (when calculating with isothermal and adiabatic compression, appropriate correction shall be made to the actual cycle), or the indicator diagram drawn when testing the air compressor with the experimental square root saw. Method 2: sound of the poker room to sign in. He is a member of the Editorial Board for the International Journal of Oil, Gas, and Coal Technology and a member of the GPSA Technical Committee Group F. Method 1: Shaft Power. Compressor data sheet shall by all means indicate maximum allowable operating … You can find this on the motor nameplate. Diesel engines and steam engines are examples of heat engines. What is the basis of eqn 5? Difference in theoretical and actual compressor calculations at inlet and outlet may reach a significant value. It should include convection and radiation heat losses. Pasquale M. Sforza, in Theory of Aerospace Propulsion, 2012. MOSS, in Biomass for Energy in the Developing Countries, 1982. A constant value of 0.8 can be used as a conservative criterion. This will inevitably lead to an increased need for shaft power. Let’s start with an example while I show you step-by-step of the calculation method. Adiabatic efficiency of the compressor is calculated as, Adiabatic efficiency, η = (Actual Polytropic work / Adiabatic work) ... Adiabatic efficiency equation . To be used in internal combustion engines, biomass must first be converted to a compatible liquid or gaseous fuel. Similarly, the data processing system should be able to correct the calculated shaft power input based on the actual inlet pressure measured during the test. Thanks What shaft power is needed to drive a reciprocating compressor that compresses 500 m3/h (295 ft3/m) of air at 25 °C from 101.3 kPa (14.7 psia) to 900 kPa (130 psia)? For an isentropic (reversible and adiabatic) process, equation 1 can be written as: The isentropic head is calculated by equation 3A: Similarly, the polytropic head is calculated by equation 3B: The actual discharge temperature based on the isentropic path is calculated by equation 4A. shaft power). Merely wanna tell that this is very useful, Thanks for taking your time to write this. Online Pump Calculator - SI-units. Did you make a linear best fit in excel in between the dependent variable k and independent variable y and arrived at the eqn.? Temperature rise. Could you please advise whether the values of ‘k’ used in the two methods were based on the Cv=Cp-R (Ideal Gas) relationship or ‘real’ values of Cv calculated directly from the EoS? Comments. Calculate the shaft power for a helical ribbon impeller with [7]: h = overall height of the helical ribbon impeller, c = wall clearance (typically 2.5% to 5% of the vessel diameter), p = pitch (ribbon height in one 360° turn), w = width of the blade (typically 10% of the impeller diameter). The polytropic exponent (n) increased by 3% and isentropic efficiency () decreased by 0.5 %. When heat capacity ratio (k) is meant, is it Cp/Cv or Cp/(Cp-R) (i.e., an ideal gas heat capacity ratio)? Calculation of the temperature increase due to compression. compression calculation is for compressor selection which is used for gas other than ... (From Figure 19-2 at 12,087 RPM for 26” compressor) Compressor Shaft HP: SHP = GHP + FHP = 939.4 + 33 ... Say compressor power consumption SHP = 1,036 BHP. The question would then be how should the thrust power be apportioned between free turbine shaft power and jet exhaust power so as to maximize the thrust power? Dr. ı want to choose a compressor for a Project For applications requiring significant mechanical shaft power (above 1 MW), direct drive type arrangements with gas turbine engines are quite popular. I appreciate if anybody help me with the equation to calculate shaft power based on flow rate and pressure. The actual discharge temperature based on the polytropic is calculated by equation 4B. and the feed composition remain unchanged. The total compressor power, which should be transmitted to the shaft, is called shaft power and may be calculated from the indicative power adjusted for mechanical losses in the compressor: N s = N i /η m. where: N s – compressor shaft power, W; η m – mechanical efficiency. Then the thrust power per unit mass is given by. Bearing and seal loss calculations relate compressor frame size (which is a function of capacity in actual cfm) and speed to power. Outlet temperature is not a good alternative to direct power measurement for efficiency calculation (such is done with compressible fluids) because high liquid heat capacity means the dT is small. HP = [144 N P1 V k / (33000 (k - 1))] [ (P2 / P1)(k - 1)/N k - 1] (1) where. The difference in the actual discharge temperatures of the SRK and short-2 values is 17.5 ˚F (9.7˚C). On the cycle diagram, the turbine provides the work necessary to drive the compressor and the free turbine provides the work to drive the propeller–gearbox combination. Power is consumed by a pump, fan or compressor in order to move and increase the pressure of a fluid. The tip of the propeller would reach sonic speed well before the flight Mach number does, which results in losses due to shock waves and in increased aerodynamic noise. The Required Power is based on inputs and is estimated for information only and does not constitute Solar's agreement to offer a firm proposal in the future. Many bearing manufacturers publish data, curves and the like relating mechanical losses to speed, clearance, and oil film thickness for various types … The purpose of a compressor (gas) or pump (liquid) is the same, to increase the pressure of a fluid by putting in shaft work (power). P1 and P2 are the suction and discharge pressures, respectively. A motor with 6 kW output and an efficiency of 0.8 will use 6/0.8 = 7.5 kW of electrical power. All the modes in the cluster are contributing at mω, leading to the canceling contributions described above. Actual conditions can vary dramatically based on location and application factors. With : Pis=Power (kW) Tsuct=Temperature inlet compre… If the Gas compression is for gas pumping for special gases … Turboprop engine showing free turbine driving propeller through a gearbox. Gaps in compressor spreadsheet of the gas horsepower going to pump. Centrifugal and axial compressors have a minimum flow point, below which they will surge. Achieving this mainly requires low exhaust temperature, hence the optimum pressure ratios are relatively high. Wood or any other form of dry biomass would be suitable in such cases. In general the power is calculated by: where  mass flow rate and h is specific enthalpy. In the compression process there are three ideal processes that can be visualized: 1) an isothermal process, 2) an isentropic process and 3) a polytropic process. where η and ηP are the isentropic (or adiabatic) and polytropic efficiency, respectively, P1 suction pressure, P2 discharge pressure, T1 and T2 arethe suction and discharge temperatures, respectively, q is gas volume flow rate at standard condition of PS and TS, Za average gas compressibility factor, k heat capacity ratio, R the gas constant, and n is the polytropic path exponent. The ideal work requirement is obtained by multiplying mass rate by the isentropic enthalpy change. 4. The full power shaft RPM of ships varies between about 80 and 150, depending on size, speed, and installed power. Assume steady state, i.e. University. Stephen Hall, in Branan's Rules of Thumb for Chemical Engineers (Fifth Edition), 2012. For mechanical integrity the combustor entry temperature must be limited to between 850 and 950 K, depending on the technology level. There are many researches on power calculation, po wer loss and performance adiabatic and reversible, The actual work is the ideal work divided by efficiency or, The actual enthalpy at the outlet condition is calculated by, The actual outlet temperature is calculated by EOS for known, Maddox, R. N. and L. L. Lilly, “Gas conditioning and processing, Volume 3: Advanced Techniques and Applications,” John M. Campbell and Company, 2, Campbell, J. M., “Gas Conditioning and Processing, Vol. Rahul Mukherjee H = Total developed head in meters = Density in kg/m 3. g = Gravitational constant = 9.81 m/sec 2 Chemo-electrical conversion in fuel cells is much further developed and is applied to specialized uses such as power supply in space craft. 2 0. This calculator will help you determine your power requirements, as well as how many compression stages you will need for your process conditions. The division of the work sent to the propeller and that sent to the nozzle is a question of some importance. For the actual gas flow rate at the inlet condition, the polytropic efficiency is close to the compressor best efficiency point (BEP). Demonstration plants for utility, domestic and industrial electricity production are in operation using clean fuels e.g. Discuss with Lewis Systems Audit Professionals the potential benefits of an energy audit in Charlotte NC, Raleigh NC, Greensboro NC and … At the frequency level of any of the flexural beam modes, the water-added mass is significant, but is simplified physically by the fact that the flexural natural frequencies are all above the level of gravity wave generation and their outward radiation at the water surface. the compressor is single stage reciprocating. This shaft is driven by an electric motor, and that motor has losses, therefore, the actual input to the motor is more than 100 HP. i.e Efficiency of the pump is the ratio water horse power to break horse power. Calculate compression ratio = R = P2/P1 The heat capacity ratio (k) was estimated by equation 5: The polytropic exponent (n) was estimated by equation 6. Fuel is added and combusted and the products exit at station 4. Intuitively, one would expect that as the flight speed approached the sound of speed, a greater portion of the work should be sent to the nozzle because the propeller effectiveness drops off as the flight Mach number increases. I would be greatful, if you could provide me the answers. 2.11). The gas mixture with the composition shown in Table1 at 105 °F (40.6 °C) and 115 Psia (793 kPa) is compressed using a single-stage centrifugal compressor with the polytropic head and efficiency curves shown in Figures 1 and 2 at a speed of 7992 rpm. Approach for evaluation of the gas turbine performance based on machine learning prediction model is shown. I appreciate if anybody help me with the equation to calculate shaft power based on flow rate and pressure. Indicated Power or Indicated Horse Power BHP Definition >Power produced on the cylinder because of the expansion of gas is called Indicated Horse Power, negating any friction, heat loss or entropy within the system. In the industrialized countries with well developed electric grid systems supplied by large hydro-electric, coal-fired or nuclear power plants, electric motors are often used to provide shaft power. If the compressor head curve and efficiency curve are provided by the manufacturer,  the head is determined from the actual gas volume rate at the inlet condition. DR. MAHMOOD MOSHFEGHIAN is a Senior Technical Advisor and Senior Instructor. For most biomass forms, conversion of biomass to a gaseous fuel is much simpler than making liquid fuels and is, therefore, the logical option for stationary shaft power applications (where fuel storage and equipment size is less important). This keeps players glued to their monitors The detail of this topic is covered in our G4 (Gas Processing and Conditioning) course. The cycle diagram for an engine of this type is sketched in Figure 10.20. In general the power is calculated by: where mass flow rate and h is specific enthalpy. 2. The water surface acts as a simple relief surface of zero transverse velocity. Further expansion through the free turbine from station 5 to station 5FT extracts sufficient work to drive the propeller–gearbox combination. These equations are used to calculate phase behavior, enthalpy, and entropy. Can the polytropic efficiency of compression be greater than unity,when n is less than k (i.e 1