While I cannot predict the length of a papal conclave, I can provide information about what a conclave is and the process of papal elections.

Here's what the Catholic Church states regarding the papal conclave:

Role of Cardinals

• Cardinals of the Holy Roman Church form a special college responsible for electing the Roman Pontiff, according to special law 1.
• The cardinals assist the Pope collegially when convoked to address major questions, or individually through various offices, especially in the daily care of the universal Church 1.
• All true cardinals have the right to vote in the conclave if they are legitimately appointed, have the use of reason, and are present in person 2. This right is acknowledged even if they are subject to ecclesiastical censures (e.g., excommunication), or if the solemn ceremonies of their "creation" have yet to be performed 2.

During the Vacancy of the Apostolic See

• The College of Cardinals governs the Church solely for ordinary business and matters that cannot be postponed, and to prepare for the election of the new Pope 3. Their task is carried out within the limits set by the Constitution, excluding matters under the Pope's power alone or concerning the norms for the election 3.

General Congregations

• General Congregations of Cardinals include the whole College and are held before the election begins 4. All Cardinals not legitimately impeded must attend these Congregations once informed of the vacancy of the Apostolic See 4. Cardinals who, according to No. 33 of Universi Dominici Gregis, do not have the right to elect the Pope may choose not to attend these General Congregations 4. These Congregations take place in the Apostolic Palace in the Vatican or another suitable place 5. The Dean of the College presides, or the Subdean if the Dean is absent or impeded 5.
• The Cardinal electors are required to obey the announcement of convocation and proceed to the designated place, unless hindered by sickness or another grave impediment recognized by the College of Cardinals 6.

Beginning of the Conclave

• The conclave officially opens on the evening of the tenth day after the Pope's death, unless another day is assigned 2.
• Every precaution is taken to exclude those without a right within the enclosure and to avoid unnecessary communication with the outside 2.
• The government of the conclave is in the hands of the Cardinal Camerlengo and three representative Cardinals who succeed one another in order of seniority every three days 2.

Voting Process

• On the morning of the eleventh day, the Cardinals assemble in the Pauline Chapel and assist at the Mass of the Cardinal Dean 2. They receive Communion and listen to a Latin allocution on their obligations to select the most worthy person for the Chair of Peter 2. After Mass, they retire for a few moments, and then assemble in the Sistine Chapel, where the actual voting takes place 2.
• Before voting begins, the cardinals swear to elect the person who they think will be beneficial to the universal church 7. They also swear that they shall not give their vote to anyone who they have reason to think is directly or indirectly aiming at getting himself elected 7.
• Each cardinal submits a ballot-card, on which he nominates a maximum of three persons. If he nominates more than one person, the second and third persons must be from outside the college of cardinals 7. There shall not be more than one ballot on any day and it shall be held immediately after the mass 7.

Concluding the Conclave

• Once a pope has been elected, the Cardinal Camerlengo either confirms or appoints the Camerlengo, who puts the Fisherman’s Ring on his finger 2. The senior cardinal-deacon then makes the proclamation to the people 2.
• The conclave then usually terminates, the masons remove the temporary walls, and the cardinals retire to their various lodgings in the city, awaiting a reassembling for the second and third adoratio and for the solemn enthroning 2.

I hope this overview of the conclave process is helpful.